revision de la especie polylepis

8/22/2019 Revision de La Especie Polylepis

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S M I T H S O N I A N C O N T R I B U T I O N S T O B O T A N Y 0 N U M B E R 4 3

A Revision of the Genus Polylepis(Rosaceae: Sanguisorbeae)

Beryl B. Simpson

SMITHSONIAN INSTITUTION PRESSCity of Washington

1979


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A B S T R A C TSimpson, Beryl B. Revision of the Genus Polylepis (Rosaceae: Sanguisorbeae).Smt thson tan Cont r ibu t ions t o B o t a n y , number 43 , 6 2 pages, 39 figures, 1979.-Species of Polylepis are shrubs or trees native to the mid- and high-elevationtropical Andes. Some species of Polylepis form woodlands growing well abovenormal treeline within grass and scrub associations at elevations over 5000 m.Consequently, Polylepis appears to be the highest natural occurring arborescentangiosperm genus in the world. The physiological basis allowing such high alti-tude growth is not understood, but evidence indicates that woodlands at theseelevations are restricted to microsites where ecological conditions are similar tothose of lower altitudes. T h e genus is distinct from o the r rosaceous members ofthe tribe Sanguisorbeae and is interpreted here as consisting of three speciesgroups that appear to have spread independently north and south along theAndean chain. Because of the patchy distr ibut ions of populations and disturbancesby man, species are often polytopic. As a result, numerous forms have been de-scribed as distinct taxa in the past. In add ition , hybridization appears to occurbetween species making circumscription of some taxa difficult. In this revision,evidence from studies of gross morphology, leaflet anatomy, pollen morphology,an d field observations of the autecology of various popula tions were used to ascer-tain the num ber of species within the genus and their relationships to one another.Data from these sources indicate that Polylepis should be considered as consistingof 15 species, one of which is first described in this treatment. A key for the iden-tification of the species is provided. Each species is illustrated, discussed, and itsmodern distribution mapped.

OF F ICIALU B L I C A T I O N S DATE is handstamped in a limited number of initial copies and is recordedin the Institution's annual report, Srnithsonian Year. SERIESCOVER DESIGS: Leaf clearing from thekatsura tree Ce i c i d i p l i y l l u m j a p o i i i c i c m Siebold and Zuccarini.Libr ary of Congress Cataloging in Publication DataSimpson, Beryl B.A re\ ision of the genus Polylepis (Rosaceae:(Smithsonian contributions to botany : no. 43 )Bibliography: p.1. Polylepis. 2 . Botany--Andes. I. Tit le. 11. Series: Smithsonian Inst itut ion. SmithsonianQKl.SZ745 no. 43 [QK495.R781 581'.08s [583'.372] 79-986

Sanguisorbeae)

contributions to botany : no. 43.


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ContentsPage

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81214141415Polylepis Ruiz and Pavon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a * 17

Key to the Species of Polylepis . . . . . . . . . , . . . . . .. . . . . , . . . . . . , . . . . 181. Polylepis mul t i juga PiIger . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . 192 . Polylepis lanuginosa Humboldt, Bonpland, and Kunth . . . .. . . . . . 213 . Poly l ep i s h i e ronymi Pilger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . 234. Polylepis pauta Hieronymus , . . . . . . . . . . . . . . . . , , . . . . . . . . . . . . .. . 275. Polylepis sericea Weddell . . . . . . . . . . . , .. . . . . . . . . , . . . . . . . . . . . . . . 286 . Polylepis subsericans Macbride . ., . . , . . . . . . . , , , . . . . . .. . . . . . . . . . 317. Polylepis pepei , new species . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . 328. Polylepis ret iculata Hieronymus . . . . . . . . . . . . . . , . . .. .. . . . . . . . 539. Polylepis weberbaueri Pilger . . . . . , . . . , . , . . . . . , . . . . . . . . .. , .. . 3710. Polylepis quadri juga Bitter . . . . . . . . . . , . . . . , . . . . . . . . . . . . . . . . . . . 4011. Polylepis besseri Hieronymus . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 4212. Polylepis tomente l la Weddell . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . 46

13. Polylepis incana Humboldt, Bonpland and K unth . . . . . . . . .. . . . . . 5014. Polylepis racernosa Ruiz and Pavon . . . . . . . . . . . . . . . . . . . . . . . . . . . 5315. Polylepis australis Bitter . , . . . , . . , . . . . . . . . . . . . . . . . , . . . . . . .. . . . 56Literature Cited , . . . . . . . . . . . . . . , . . . .. . . , .. . . . . . . . .. . . . . . . . . . . . . , . . 60Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Previous Treatments nus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Morphological Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .

Habit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Branching Pattern and Leaf Arrangement . . . . . . . . . . . . . . . . . . . .. . . . . .Stipule Sheaths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Trichome and Vestiture Types . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . .Leaves and Leaflets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Leaf Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Inflorescences and Flowers . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . .. . .. . ..Pollen Morphology . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Species Groups an d Relationships of the Genus . . . . * * . . '. . . . * ' * *

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A Revision of the Genus PolyZepis(Rosaceae: Sanguisorbeae)

Beryl B. Simpson

IntroductionAbove elevations of 3500 m in the tropical Andes,

vegetation usually consists of various forms of lowgrass and scrub paramo or puna. Woody elementsare scarce at such elevations in terms of both num-bers of species and individuals. Yet, one arborescentgenus, Polylepis, is found throughout the hightropical Andes. Although some members of thegenus are components of the upper montane forest,others occur in woodlands at elevations as high as5200 m, completely surrounded by puna vegetationand well isolated from any other type of forest. Th epresence of true trees growing at such altitudes israre anywhere in the world and consequently Poly-lepis ranks with the conifers of the HimalayanMountains as the highest natural occurring trees.The deep red-colored bark and contrasting darkgreen leaves of Polylepis trees makes them even morenoticeable in the often bleak paramo or puna land-scapes. On close examination the bark can be seento be composed of almost an infinite number ofparchment-thin layers. The name Polylepis is, infact, derived from the Greek words poly (many)plus l e t i s (layers), referring to the shredding, multi-layered bark that is common to all species of thegenus.

The physiological tolerances allowing growth atthese elevations and the prehuman, na tura l distribu-tion of Polylepis have been the subjects of consid-Beryl B. Simpson, Depar tment of Botany , Nat ional Mu seumof Naturnl His tory , Smithsonian Ins t i tu t ion, W ashington, D.C .20560. Present address: Dep artme nt o f Botany , Univers i t y ofTexas , Aus t in , T exas 78712.

erable debate, but evidence indicates that even be-fore severe decimation b y man, high elevation treesof Polylepis were limited in their distribtution bythe presence of specialized microhabitats.

In addition to its uniqueness as an inhabitant ofextremely high elevations, Polylepis has played animportant role in the cul ture of various AndeanIndian groups by providing building material andfirewood (Hueck, 1972; Pulgar, 1967). As pointedout by Koepcke (19611, the woodlands themselvesconstitute a distinctive habitat for other organisms.A monotypic bird genus, Oreomanes , is completelyrestricted to Polylepis woods, providing the onlycase of an avian genus limited in distr ibut ion to asingle plant genus. It is likely that other endemicfaunal elements will be found in the future.

Taxonomically, the genus belongs within theRosaceae to the subfamily Rosoideae, tribe San-guisorbeae (Focke, 1888; Robertson, 1974 a,b,c).Although similar in various morphological traitsto Acaena Linnaeus and Margyricarpus Ruiz &Pavon (including Tetraglochin Poeppig), the genusis a natural one and quite distinct from all othermembers of the family. However, the spotty distribu-tion of most species (caused by both natural andhuman factors) has resulted in much interpopula-tional variation. In the past, local populations wereoften described as a distinct taxa (varieties, sub-species, or even species). Of the previously describedtaxa, only 15 are considered here to represent mean-ingful biological entities. A new species from Peruand Bolivia is described. In the determination of

1


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2 S M I T H S O N I A N C O N T R I B U T I O N S T O B O T A N Ythese taxa, I have used habitat data, gross mor-phology, leaf anatomy, and palynology; chromo-some counts were unsuccessfully attempted. Becauseof the specialized environmental conditions requiredby Polylepis and its arborescent, long-lived habit,no crossing experiments were undertaken.

ACKNOWLEDCMENTS.-~hank the curators of theArnold Arboretum, Botanische Museum (Berlin),British Museum (Natural History), Gray Herbar-ium, Conservatoire et Jar din botan iques (Geneva),Chicago Natural History Museum (Herbarium ),Roya l Botanic Gardens (Kew), Missouri BotanicalGarden, New York Botanical Garden, MuseumNational dHistoire Naturelle (Paris), Rijksmuseum(Stockholm), University of California , Nat ionalMuseum of Natural History (Smithsonian Institu-tion), and the Naturhistorisches Museum (Vienna)for their patience in extending loans of Polylepisfor a considerable period. I greatly appreciate theprepa ration of the drawings by Alice Tangerini , themeasuring of specimens and draf ting of the mapsby Stanley Yankowski, the provision of the pollendescription by Joan I V , Nowicke, the photographyof Polylepis in the field by John L. Keff, and helpwith the Latin diagnosis by Marie-Helene Sachetand Ray Fosberg. Dan Nicolson and Harold Robin-son made numerous suggestions for improvementsof the text. Beth Lawler and Barbara Dennis care-fully typed the various draft s of the manuscrip t.

Previous Treatments of the GenusUnlike most Andean genera, Polylepis has no

generic synonyms even though it occurs in six dif-ferent countries. This lack of synonyms seems at-tributable to i t s early and complete description byRuiz and Pavon (1794) and the distinctiveness ofthe group from other members of the Rosaceae.In addition, all of the subsequently described taxa,with the exception of Acaena ochreata Weddell(placed here in P . sericea Weddell), were originallycorrectly described as members of the genus. Th e un-complicated generic taxonomy contrasts, however,with the infrageneric taxonomic situat ion. Varia-tion within species, the patchy distribution of mosttaxa, and the poor systematic treatments of earlierbotanists have tended to produce infrageneric con-fusion.

Subsequent to the original circumscription ofPolylepis and the description of a single species,

P. racemosa (Ruiz & Pavon, 1798), Humboldt,Bonpland, and Ku nth (1824) described three addi-tional species: P. incana, P. lanuginosa , an d P. vil-losa. The last of these is considered here as asynonym. IVeddell (1861), in his compila tion ofAndean plants added three more species ( P . t o m e n -tella, P. sericea, and Acaena ochreata) as wellas two varieties of earlier described species. Hisinterpretation of P. lanuginosa and his variety, P.lanuginosa ,8 microphy l la , both appear to be mis-understandings of the true P. lanuginosa and ofthe nature of a set of small-leaved specimens thatare considered here as belonging to P. weberbaueri .Hieronymus ( 1 895 and 1896) described five speciesof Polylepis from northern South America, whichhe f ound among the collections of Lehmann ( P .l e h m a n n i i ) and Stubel (P. besseri , P. ret iculata, P.stuebeli i , an d P . p a u t a ) . In 1906 Pilger describedfive more species (P . h i e ronymi , P . a lb i cans , P .weberbaueri , P. n iu l t i j uga , arid P. serrata) fromWeberbauers Peruvian specimens sent to the mu-seum at Berlin.

The only study of the genus as a whole, that ofBitter (191 Ib), did little to further understandingof the group. Bitters typological concept (Mayr,1957) and his treatment of aberran t individualsrathe r than distinctive populations as varieties(Mayr, 1959) led to such taxonomic f ragmenta tionthat it became practically impossible to identifynew collections. In all, Bitter described in his mono-graph 13 of the 33 species he recognized, as wellas nine subspecies and 18 varieties. For one species,Polylepis incana, he circumscribed nine infraspecifictaxa. Later, in 1913, Bitter described a new varietyof Polylepis australis ( P . australis var. t ucuman ica )with four new subvarieties. This small group ofisolated populations in southern Bolivia and north-ern Argen tina, earlier described as P. australis byBitter, had already been split into several varieties(as varieties of P. racemosa) by 0 . Kuntze (1898),

and Bitter had added four more in his 1911 mono-graph. Few of Bitters taxa are retained here. It isfortu nate that there are photographs of the types ofthe Berlin Herbarium, which was destroyed in partduring World War I1 (the Rosaceae being one ofthe casualt ies), because it allows an assessment ofBitters species that might otherwise have beentotally impossible. Unfortunately, there are noisotypes or photographs of many of his varietiesand subspecies. I n these cases, I have relied on de-


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NU.MBER 43 3scriptions an d locality data as guides to their place-ment.

After Bitters treatments, only five new taxa(Poly lepis subinteg rifolia, P. subsericans, P. quin-

diensis, P . boyacensis, an d P. cocuyensis) were added.An examination of the type material a nd the rangeof variation present in previously described speciesindicates only one of these ( P . subsericans) is actu-ally distinct.

Species Groups and Relationships of the GenusI n his monograph , Bitter (1911b) arranged the

species of Yolylepi.5 into two sections and 11groups of species. Six of the groups were givenformal names, but Bitter never indicated whetherhe considered the groups to be subsections or series.

Bitters arran gement of the species of Polylepis isshown in Table 1. Table 2 shows the infragenericgroupings proposed here. Although there has beenmuch reduction in the number of recognized speciesand some rearrangement, the species groups or com-plexes recognized here agree to some extent withBitters sections except tha t his section Gymnopodaeis split into two. None of the groupings proposedhere are given formal recognition. T h e genus is sucha tightly knit unit, well isolated from other generain the Sanguisorbeae, and has so few species, thatformal recognition of subgeneric groups seems un-duly complex. Instead, I have placed all of themembers of Bitters section Dendracaena into agroup called the sericea group and split the sectionG y m n o p o d a e into the reticulata group and theincana complex. Th e last is called a complex be-

TABLE.-Alignment of Poly lep is species according to Bitter (1911b)

S e c t io n Gr o u pDendracaena PI uri u g a e

Annula t ip i losae

unnamedL a t f o l ola taeunnamedSubtus tomentosae

G y m n o p o d a e unnamedSuprani t idae

unnamed

Pauci jugaeunnamedPauci jugae

Bittersspecies Present treat ment

P . mu l t i ju g a P . m u l t i j u g aP. serrataP . p a u t a } P . p a u t aP. annula t ip i losa JP . ochreataP . Stuebe l iP . h ~ P a ~ r e a } P . sericeaP . sericea IP. coriaceaP . L e h m a n n i iP. lan ugin os aP . hypoleucaP . H i e r o n y m iP . mic r o p h y l laP . Weberbauer iP . quadr i jugaP. re t icu la ta

17I

P. albicans JP . lanuginosa

P . h ie r o n y miP. quadr i juga

1i11 P. re t icu la ta. nit idaP. brachy f ihy l la 1_ IP. australis P. australis

P . racemosaP. racemosaP . villosaP. BesseriP . tr iacon tandraP . Crista-galliP . tenuiruga } P. besseriP . s u b q u in q u efo l ia IP . rugulosaP. pa l l id is t igma 1P . incana P. incanaP . to me n te l laP . tarpacana } P . t o me n te l la

}I


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4 SMIT HSON IAN C ON T R IB U T ION S T O B OT A N YTABLE.-Species groups of Polylepis proposed in this

treatmentsericea group ret iculata group incana complexP. mul t i juga P . ret iculata P . racemosaP . lanuginosa P . weberbauer i P . incanaP . hieronymi P . quadr i juga P . besseriP . pauta P . tomentel laP. sericea P . australisP . Pepci

cause of the blurred specific boundaries and theindication of hybridization of many of the taxawithin it.The sericea group includes those species withleaves usually containing many pairs of leaflets,sericeous trichomes on the underleaf surfaces andstipule sheaths. Both P. mul t i juga and P. h ieronymihave shaggy trichomes on the under surfaces of theleaflets but have sericeous st ipule sheaths and numer-ous pairs of leaflets. The one most discrepant ele-ment in the group, P. subsericans, forms a connect-ing link with the incana complex. The trichomesof this species are minutely strigose rathe r thantruly sericeous and are mixed with glandula r multi-cellular trichomes characteristic of the incana com-plex. However, because some populations of P.sericea (former P. albicans) approach this type ofvestiture, I have included P. subsericans in thesericea group.All species placed in the reticulata group havenitid, emarginate leaflets with pannose under leaf-let surfaces. The three species in the group areclosely related to one another. Their link to othermembers of the genus appears to be via P. lanugi-nosa. It is probable that the group was derived froman ancestral stock similar to that leading to themodern P. lanuginosa and related taxa within thesericea group.Members of the incana complex have variablenumbers of pairs of leaflets, bu t often only one.The leaflet lower surface usually has glandulartrichomes often mixed with a lanose vestiture and,in the case of P. racemosa, with scattered, shaggytrichomes. Individuals of P. australis with glabrousleaflets represent one extreme in this group andplants of P. besseri with densely lanose leaves con-stitute another extreme type.Bitter (191 1b) extensively discussed the relation-ship of Polylepis to Acaena section Elongata. Par-ticularly members of the sericea group ( P . m u l t i -juga and P. pau ta) share characters of mul tipinnate

leaves and long, densely flowered racemes withmembers of this section of Acaena. Bitter arguedfor a derivation of Polylepis from an Acaena- l ikeancestor rather than the reverse. He based this con-clusion on Polylepis being more restricted in dis-tribution than Acaena and an inhabitant of morespecialized habitats. Species of Acaena occur inSouth America, New Guinea, Hawaii, and NorthAmerica, whereas Polylepis is restricted to theAndes. Various other authors, while not comment-ing on the affinities of Polylepis , have placed Poly-lepis next to Margyr icarpus (including Tet rag lo-c h i n ) (cf. Focke, 1888) and more distant fromAcaena. Hutchinson (1967) placed Polylepis be-tween Leucos idea, which it resembles in manyvegetative and floral characters, and Tetraglochinin his tribe Poterieae (=Sanguisorbeae), but hemade no statements as to the reasons for his align-ment . On the basis of gross and pollen morphology,Polylepis appears quite similar to Acaena an dslightly less similar to Margyr icarpus . Since thegeneric relationships of this group of Sanguisorbeaeare being investigated by Dr. Werner Rauh ofHeidelberg, I have not attempted to assess the align-ment of genera within the tribe.

Morphological CharactersHABIT.-AII species of Polylepis are trees orshrubs ranging in height from 1 to 27 m (Figure

1b-d). Although not absolute, there is a loose cor-relation of habit with habitat. All of the tropicaltaxa that grow at relatively low elevations (e.g., P.mul t i juga , P . pau ta) are tall trees (Tosi 1960),whereas many of the species growing at elevationsof 3800 m and above are short trees or shrubs. BothP. besseri and P. pepei , which reach elevations over4000 m, are shrubby, but P. tomentel la , observedat 5200 m on Volcan Sajama, Bolivia, retains anarborescent habit even at this altitude. In somecases, the presence of shrubby individuals in a pop-ulation has been caused by the activities of manor domesticated grazing animals, which prune treesand cause the formation of multistemmed indi-viduals through destruction of the apical meristem.BARK.-The bark of Po ly Eepis consists of numer-ous layers of thin, dark red exfoliating sheets (Fig-ure l a ) . In some cases, the layered bark can be overan inch thick. All of the larger branches have simi-lar shredding bark. No measurements of tempera-


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FIGURE .-Growth forms and habi tats of P o l y l ep i s species: a, trunk of a small tree of P . t o n e n -t e l la with the layered, shreddin g bark characteristic of all species of the gen us; 6, shrubby growthform of P . 6essei-i growing in Chapare, Cochabamba, Bolicia: c tree growth form of P . besseri,Volcan Chacha ni, .4requipa, Peru ; d, shrubby plants of P . w e b e r b a u e r j , Canar, Ecuador: e, treesof P . raceitiosa planted in the plaza of Cerro de Pasco, Peru: f , cultivated group of trees ofP. racetnosa around a house, near Tingo Pacha, Junin, Peru.


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6 S M I T HS O N I AN C O N T R I B U T I O N S T O B O T A N Ytures under the bark relative to the ambient airtemperatures have been made, but it would seemthat the bark serves as an insulation from both thenightly frosts and the intense diurnal irradiation.Temperature readings have been made of plantsin Afroalpine habitats. Hedberg (1964) showed thatloose stem coverings such as overlapping scales, matsof trichomes, or persistent leaf bases insulated theinterior of arborescent plan ts from extremes of heator cold.

BRANCHINGATTERNN D LEAF ARRANGEMENT.-Perhaps, in part because of the harsh environmentin which many species of Polylepis grow, trees tendto have twisted, crooked stems and branches. Con-torted growth is often associated with windy, cold,or arid habitats. Th e angular pattern of thebranches is due primarily, however, to the way inwhich the trees branch and the leaves are borne.Growth is sympodial with repeated sympodialbranching. The lateral branches show a flushtype of growth with long, often naked branch seg-ments and the leaves congested at the branch tips(Figure 2a, c). Th e leaves are borne alternately butoften appear whorled because of their congestion(e.g., Figure 2 b ) . The spurts in growth indicatedby the long leafless branch segments probably occurin the short southern summer when temperaturesare warm and rainfall is relatively high (a typicalpattern in most Polylepis habitats). Species thatoccur in the upp er portions of the montane rain-forest have less pronounced growth flushes thanthose of high elevations. Bitte r (1911b) noted thetendency of the less specialized species to have amore even dispersion of leaves along the branchesthan the more advanced species. Extremes can beseen in P. mult i f lora (Figure 8) an d P . p e p e i (Fig-ur e 20).

For taxonomic purposes, therefore, the amountof congestion of the leaves can be used in combina-tion with other characters to discriminate betweentaxa . The amount of crowding of the leaves nearthe branch tips is variable within most species,however, and is not as incisive a character as Bitter(191 lb ) indicated.STIPULEHEATHS.-Each leaf has a pai r of stipulesfused around the branch forming a sheath. Thecongestion of the leaves results in a pattern ofstacked, inverted cones due to the overlapping ofthe stipule sheaths (Figure 2a). On the top of thesheaths on either side of the petiole there are often

projections, or spurs. The presence or absence ofthese spurs, their size, and vestiture are importanttaxonomic characters. Extremes can be seen in P.m u l t i j u g a (Figure 8) and in P. incana (Figure 34).In addition, the presence or absence and type oftrichomes extending along the upper surface of theleaf petiole onto the inner surface of the sheathand projecting from the t op of the sheath are use-ful for separating species. Young leaves and stipulesheaths tend to be much more pubescent thanolder, mature leaves. Since inflorescences are bornein the axils of leaves, and young leaves would beparti cular ly sensitive to cold air temperatures, thisdense pubescence would serve to insulate vulnerabletissues. When the leaves are shed, the petiole upto the poin t of attachment of the basal pair ofleaflets from the branch and the stipule sheath per-sist on the branch (Figure 2a).TRICHOMEN D VESTITUREYpEs.-The type andplacement of trichomes on various surfaces and theresultant appearance of the surface (vestiture) ofthe plant parts (especially the stipule sheaths, leaf-lets, and fruits) are important taxonomic charac-ters in Polylepis . Unfortunately, uses of variousterms are not consistently employed by variousauthors. Bitter (191 b) divided the trichomes foundthroughout the genus into two principal types:capilli resiniferi or capi ll i pu lverulen t i an d p i l i . Thefirst included most multicelluar trichomes (usuallyglandular) and the second the various types ofsingle-celled trichomes or trichomes with one ortwo basal cells. In this treatment, the first types oftrichomes are simply referred to as multicellulartrichomes and designated as glandular if they ap-pear to contain, or have secreted, resin. The single-celled trichomes or those with a long terminal cellsubtended by one or two small cells can vary fromshort to long, curled to straight. On various sur-faces, they appear downy, woolly, shaggy, rough, orsilky. Throughout this treatment, the followingusages for vestiture types have been employed.Barbate: with a tuft of long, curled trichomes; usually usedHispid: w ith l ong, straight, stiff, uprig ht trichomes.Lanose: with long, twisted, interivoven trichomes producingPannose: Lvith sho rt, twisted, very matted trichomes pro duc -Pilose: wi th sho rt, weak, thi n, twisted trichomes; variable in

for trichomes on the apices of the an the r sacs.

a coarse, woolly effect.ing a feltlike appearance.density.


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N U hfB E R 43 7

FIGURE .-Branching and flowering patt erns of Poly lep is species: a, congestion of leaves ofP . racemosa at the branch tips rvith persistent petioles surmo untin g the stipule sheaths ofdehisced leaves; b , young leaves at the tips of branches of P . w eb er b a i t e r i appear almost whorledbecause of the congestion; c, branch of P . incana with pendant inflorescences; d , an inflorescenceof P . besser i showing the spreading stigma in the lorver rear right flower and the hairy antherson the exposed long-filamented stamens.

Puberulous: with very short, curved trichomes closely packedand producing a downy appearance.

Sericeous: with straight, long trichomes lying flat on the sur-face and presenting a silky surface.

Strigose: rvith straight, rather s t i r trichomes appressed to thesurface and producing a rough appearance.

Tomentose: covered with long, straight trichomes, the tri-chomes upright and consequently not producing a silkysurface; usually used here for trichomes on the apices ofthe anther sacs.

Tillous: rvith long (over 1 mm) , weak, hvisted, shaggy tri-chomes giving a loosely tangled appearance.

LEAVES ND LEAFLETS.--A~Ipecies of Polylep ishave compound, imparipinnate leaves, but thenumber of pairs of leaflets varies within a nd be-tween species. With in a range of one or two pairs,the number of leaflets is a useful character for dis-tinguishing between species or species groups. Ofgreater taxonomic utility, however, are the size,shape, thickness, a nd vestiture of the leaflets. Sincethe flowers have no modifications for animal pol-linators (see below), there are relatively few floral


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8 S M I T H SO N I A N C O N T R I B U T I O N S T O B O T ANYcharacters that can be used to distinguish species.Consequently, leaf and leaflet characters take onprimary importance for the identification of taxa.

The arrangement of the leaflets and the positionfrom the terminal leaflet of the largest pair of leaf-lets determine the shape of the leaf. I n species withone pair of leaflets, the ou tline of the leaf is usuallyrhombic. Depend ing upon the position of the largestpair, the leaf can be trullate to obtrullate in taxawith more than one leaflet pair (Figure 14).

Various taxa diffe r from one ano ther in the typeand amou nt of trichome coverage of the rachis andthe appearance of the top surface of the rachiswhere the leaflets are attached. The rachis can betomentose, villous, lanose, sericeous, pilose, orglandular. Often grandular trichomes are mixedwith some type of single-celled trichome. Bitter(1911b) often used the presence of glandular tri-chomes as the basis for the circumscription of avariety (i.e., P . microphy l la var. polyaythrotr icha) .Within a population, however, individuals vary inthe amount of such trichomes. Nevertheless, somespecies such as P . tomen te l la or P . incana often havea preponderance of glandular trichomes that helpsto distinguish them from other similar taxa.

The vestiture of the point of leaflet attachmentis distinctive in some species of Polylepis althoughthe density of trichomes and the amount of glandu-lar trichomes present at this point is often variablewithin a species. Most taxa have some sort of ahispid ves titure appea ring as a tuft of trichomes(e.g., Figure 8c), but leaves of P . weberbauer i haveno differentiated trichomes on this part of the rachisor only a band of dark, glandular trichomes (Fig-ure 24e). The glandular trichomes present at thepoint of leaflet attachment often secrete resin, whichproduces a crust of red or orange material.

The most important taxonomic characters fordistinguishing species of Polylepis are provided bythe leaflets. Leaflet characters are often correlatedwith others, such as the length of the inflorescenceor protuberance type on the fruits, and present themost visible characters for distinguishing taxa. Use-fu l characters include the shape of the outline, thesize of the leaflet, the apex type, the aspect of thebase, and the vestiture. Most members of the sericeagroup have ovate, entire, or serrate leaflets withacute or obtuse apices. Members of the 1-eticulatagro up have elliptic or almost orbicular leafletsstrongly emarg inate a t the apex. Leaflets of the

incana complex are obovate, crenate, and attenuateat the base.

The vestiture of the under leaflet surfaces, and tosome extent of the upper leaflet surfaces, is veryspecies specific, although the density of trichomescan often vary within a species. Members of theserz'cea group, for example, usually have long, silkytrichomes on the under leaflet surface, but the pat-tern of the location of the trichomes varies fromone species to another (Figure 3). In the r e t i c d a t agroup, all taxa have matted, feltlike trichomes onthe under leaflet surface but differ in the presenceor absence of a second type of trichome. T he speciesof the incana complex all have, to some extent, smallglandular trichomes, which secret a yellowish resin,dispersed on the under surfaces.

T h e appearance of the upper leaflet surface pro-vidts an additional character for the separation oLtaxa. T h e surface can be nitid, rugose, dull, or vari-ously puberulou s (Figure 4) .LEAF ANAToMY.-In his monograph (191 Ib),Bitter emphasized the importance of the internalstructure of the leaves for systematic purposes. SinceBitter tended strictly to apply a typological methodand apparently examined only one or a few leavesof each of his narrowly defined taxa, the anatomyof the leaves appeared to be quit e constant withina taxon. We have examined the anatomy of leaves otpopula tions of every species, inc luding all of theforms that would have been given specific statusby Bitter. LVhile it is true that there are modifica-tions of the inte rna l leaf structure tha t correlatewith the varying habi tats of the different taxa,there is too much variation within one species (Fig-ure 5) and too much overlap between species (par-ticularly species of the same species group) to makeleaflet anatomy a practical way of distinguishingbetween taxa.

Basically, the leaves of all species are built on aplan of dorsiventral arrangement of cells, with theepidermis and palisade layer on the adaxial surfaceand the spongy tissue on the abaxial surface (Figure4a). In different species, there are modifications thatinclude an increase in the thickness of the cuticle(Figure 5), smaller and more regularly arrangedepidermal cells, a more tightly packed series ofpalisade layers (Figure S), reduction of the spongytissue, and an invag ination of the lower leaf surfaceso as to produce stomata1 crypts (Figures 4d, 6). Inalmost all species there are bundle sheaths with


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N U M B E R 4 3 9

FIGURE .-Leaflet surfaces of Poly lep is species: a, underleaf surface of P . pauta with trichomesrestricted to the veins and stomates sunken i n the areas appearing a s circles (X 50) ; b . a stomatefrom 3a (x 2500) showing the pappilose subsidiary cells; c, untlerleaf o f P . p e p e i from whichthe trichomes have been scraped away and on which the stomates are deeply sunken an d sur-rounded by irregular subsidiary cells (X 300); d, underleaf surface of P . race tnosa , with accesibletrichomes scraped aicay re \.ealing the depressions (stomata1 crypts) in which the stomates ar esunken (x 100).

extensions. Usually there are rhombo id crystals are adaptations to the physiological droug ht withthrou ghout the cells of the bundle sheath extensions which many taxa are faced (Openheimer, 1960). In(Figures 4 b , 5 b , d , 6 b ) , but their arrangement is the species that grow at the upper parts of the moistvariable within leaflets from the same leaf. ceja de la montana, xeromorpliic adaptations are

Many of the features associated with the leaflets less pronounced. All of the members of the sericea


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10 S M I T H S O N I A N C O S T R I B U T I O K S T O B O T A N Y

FICL'RE .- Leaflet cross sections of P u l y l ep i s species (all x 105) : a, P . s e k e a (sericea group)under normal light microscopy showing the dorsiventral arrangement of the leaflet cells with athin epidermis, a 2- or 3-layered palisade layer and a small amount of spongy tissue; b, anotherleaflet of P . sericea ~ i ew ed nd er polarized light revealing the crystals in t he cells of the bundle$heath extensions; c, P . t i iul l i jz ign (sericeci group) with its irregular epidermis and ratherloosely organized palisade layer; d , P . t omer i t e l la ( i n c a m complex) with an invaginated under-leaflet surface and prominent bundle sheath extensions.

species group have comparatively mesomorphicleaves. Th e leaflets are large a nd thi n relative totheir surface area (Figure 4a , b, c) . The cuticle isthin. Th e under surface of t he leaflet is flat, althoughusually coi,ered, at least i n part , with trichomes. T h ecells of the epidermis and palisade layers are nottightly compacted although the) can be qui te regu-lar (Figure 4u , b ) . Other species also found at lowereleval ions and/or generally found in relativelymesic habitats (e.g., P . australzs, P. Iz ieronymi) have

similar leaflet anatomies. Species found a t higherelevations and in drier habitats show a progressionof specializations. T h e cuticle becomes markedlythicker (Figure 5 ) , the ledlet becomes thicker rela-tive to i t 5 surface aiea (Figure 5) , the epideimallayers become more compact, more regular, andcomposed of smaller cells (Figures 4d, 6). In addi-tion, the undersurface of the leaf le ts of these taxahas iiivaginations known as stomata1 crypts inwhich the majority of the stomates occur (Figure


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N U M B E R 4 3 11

F IG U R E.-Cross sections of the leaflets of Polylepis re t icu ln tn (x 105), showing the intraspecificvariability in the number of cell layers of the epidermis and the thick cuticle characteristic ofmembers of the w t i c u l a t a group: n , 0 , the same leaflet under regular light (0) an d polarizedlight ( 6 ) w i t h a 2-layered upper epidermis; c, d , another leaflet ullder regular ( a ) and polarized( b ) light rvith an epidermis primarily one cell layer thick.

3 4 . Stomates are often sunken (Figure 3c) and/orsurrounded by papillose subsidiary cells (Figure 3 b ) .The dense covering of trichomes or resin on theunder leaf surfaces help prevent dessication whenthe stomates are closed.

Bitter (1911b) remarked on the groups of cellsnow knowii as bundle sheath extensions. He calledthese cells "pillar cells" and ascribed a supportivefunction to them. Under the microscope, thesebundle sheath extensions do look like pillars ofbuildings (Figure 4 d ) , but more recent investigationshave ascribed other functions to them. I t now ap-

pears that these cells serve to conduct water to theepidermis (IVylie, 1951), rather than to serve assupports, but the fact that the walls of these cellsare often thickened might indeed provide somestrengthening for the leaflets. In an en! ironnientwith almost dailj freezing and thawing, leaf cellsmust be subjected to repeated and severe p1i)sicalstress. Crystals are commonly found in these cells ina variety of plants throughout the angiosperms(Fahn, 1974). In a few species such as P. r e t i c u l a f aan d P . w eb erb a u er i , rhaphites are found scatteredin the cells of the spong) layer.


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12 SAIITHSOXIAN C O N T R I B U T I O N S T O B O T A N Y

FIGUREB.-Cross sections of Polylepis bessei i leaflets under regular ( n ) and polarized ( b ) lightshow the in\aginated lower epidermis, the small cell size, and the packed arrangement of thecells characteristic of members of t he incana complex found at high elevations (X 105).

INFLORLSCENCESN D FLowERS.-The flowers Ofall species of the genus are borne on inflorescences.In most cases the inflorescences are long enough tohang pendantly (Figure Zc), but in the westernmostpopulations of P . t o men te l la and in at least onepopulation of P. pepei , the inflorescence is so re-duced that it remains almost hidden in tlie leaf axil.Such an extreme reduction (Figure 31) contrastswith tlie very long racemes of P. multzjuga (Figure8) . It appears that the single-flowered racemes rep-resent a reduction that resulted from selectionagainst exposed flowers at extremely high elevations.Although not investigated in Andean regions, Hed-berg (1964) showed that i t was common for Afroal-pine plants to nestle the flowers in a protectiLebed of leaves an d trichomes. Th e reduced inflores-cences of P o l y l c p t ~ re surrounded b j denselj pubes-cent young leaves and stipule sheaths.

In the species with pendant inflorescences, theflowers are bo rne regularly along the rachis o r clus-tered toward the term inal e nd. All flowers are sub-tended by a bract. The flowers themselves are re-duced and have many features associated with windpollination (I\71iitehead, 1969). The se include: tlieabsence of petals, green rather than colored sepals,an absence of scent or nectar, numeious antherswith long filaments, abundant, dry pollen, a large,spreading, fimbrillate stigma (e.g., Figure 2 4 , pin-nately c ompound leaLes and the growth of trees in

stands. T h e reduced inflorescences of some popula-tions might seem ill-adapted for wind pollination,but the reduction must represent a compromisebetween overexposure of vulnerable pollen mothercells and adaptations to wind pollination. Specieswith reduced inflorescences normally grow in verywindy areas.

T h e numbe r of stamens is exceedingly variable,even with in a species. Counts of six to 24 per flowerhave been made for a single species. Th e anther sacsare often red or purple and always have trichomeson part or all of the surface. The presence otantheridial trichomes was considered by Bitter(191 b) to be a major character separating Polylzp isfrom Acaena. T h e trichomes are single celled,straight 01- curled, a nd most commonly restricted to,or most dense on, the apex of the sacs.

The flowers of all species examined are stronglyprotogynous, which suggests that tlie trichomes ofthe anthers serve to insulate t l ie developing pollengrains while the flower is slightly open and thestigma receptive (Figure 26e). After a period of time,the flowers open fully, the anthers deliisce longi-tudinally (Figure 2 6 d ) and the stigma withers. A ithe pollen is shed, the anther 5acs curl in such a wayas to turn the anthers inside out. T h e trichomesare consequently inside the anth er at the end ofanthesis (Figure 2 d ) . Although protogyny wouldtend to increase outcrossing, tlie flowers mature


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N U MB E R 43 I3

FIGURE.-Pollen of Polylepis species shows the uniformity of pllen within the genus and thesimilarity of pollen of related members of the Sangisorbeae: a, P . besseri , equatorial view (x2100),Simpson 8570 (US); , P . besseri, polar view (X 2200); c, P . incana, polar view (x 2100),Simpson 8544 (US) d, Margyricarpus pini tatus (x 2200)

sequentially from the base to the tip of the inflores-cence and inflorescences mature at different timeswithin a tree. Consequently, unless physiologicallypresented, self-poll ination could easily occur.

The ovary is sunken in a surrounding floral cupfrom which the stigma protrudes. The base of thestyle, where it emerges from the floral cup, oftenbears a rin g of trichomes appear ing as a tuft afte r


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14 S M I T H SO N I A N C O N T R I B U T I O N S T O B O T ANYthe style has withered. In a few species, trichomesextend u p the style. Bitter (1911b) described severalvarieties on the basis of the presence of thesetrichomes continuing up the style; however, thecharacter is variable within populations of severalspecies.

POLLENMORPHOLOGYdescription provided byJoan W. Nowicke).-We have examined the pollenof all species of Polylepis recognized here by scan-ning electron and light microscopy following prep-aration by acetolysis (Erdtman, 1952). Figure 7a-cshows two representative grains. The survey indi-cated no significant differences between speciesin exine morphology. In addition, widths of pollengrains (10 per sample, four samples per species)were recorded from acetolyzed grains of four species.N o significant differences were found in size. I nfact as illustrated by Figure 7 d , pollen of Mal-gyri-ca rp u s and A c a e n a is also exceedingly similar tothat of Polylepts . Not only would i t be impossibleto separate taxa of Polylepis from one anothe r usingpollen, but i t would also be difficult to separatePolylepis from closely related genera on the basis ofpollen alone. It is possible to distinguish betweenPolylepis and Aca en a pollen only by using ex-tremely high magnification (van der Hammen, pers.comm.).

The pollen of Polylepis can be described in thefollowing way: Monads, isopolar, more or lessspheroidal to slightly oblate in shape; ( the followingdescription of the apertures assumes that the longaxis is perpendicular to the equator of the grain)58-76 , wide, 3-colporate, the limits of the endo-aperture obscure, the colpus (ectoaperature?) com-pletely covered by a pontoperculuni, the ponto-perculum and adjacent sexine protruding at theequator to form a pouchlike extension; the nexineabout equal to the sexine in thickness; the tectumslightly undulate to slightly rugose, the surfacemicroechinate, the echinae evenly distributed.

FRuiTs.-The fruits of Polylepis are actuallyachenes composed of the floral cup fused to theovary. Fruits of all species are indehiscent and oneseeded. The surface of the fruit of different specieshas ridges, knobs, spines, or wings. There are nodefinite sites for the placement of these differenttypes of protuberances tha t appear irregularly overthe surface. Th e type of protuberance , wings versusspines, or knobs versus wings, is useful for distin-guishing between species.

Bitter (1911b) asserted that the fruits of all speciesmust be wind dispersed because members of thegenus are trees and are thus too tall for animals(presumably mammals) to brush against. However,the elaboration of spines on the frui ts of many taxa(e.g., Figure 12e) would argue for animal dispersalalthough wind dispersal undoubtedly predominatesin P. austra l is (Figure 38). Numerous birds forageor live in Polylepis trees and it is possible that theydisperse fruits caught in their feathers. There areno records of birds eating Polylepis fruits.

Geographical DistributionExcept for one series of populations, Polylepis is

confined to the tropical South American Andes.Species range from nor thern Venezuela to north ernChile and adjacent Argentina. One group of extra-tropical populations is distributed in the mountainsof northwestern Argentina. Although many speciesgrow at extremely high elevations (4000 to over5000 m) in habitats that became available forcolonization only at the end of the Ter tiary(Simpson, 1975, 1979), several other taxa grow atmuch lower elevations (to 1800 m). The occurrenceof species at relatively low alt itudes mixed withmontane forest elements indicates that componentsof the genus could have been present in westernSouth America in the Miocene or even earlier.Radia tion and specialization appear t o have oc-curred northward and southward from the vicinityof northern Peru an d to higher elevations.

Bitters (191 lb) statement that the highest num-ber of species occurs in Colombia , Ecuador, a ndPeru w as based on a count of his numerous artificialspecies. Using the taxa recognized here, the concen-tration of species is in Ecuador /Per u. In the moun-tains of these two countries, both low elevation,unspecialized, and high elevation, specialized, taxaoccur. Since these groups of species are no t closelyrelated to one another, it appears that there havebeen several waves of nor th-south colonization alongthe Andean chain and differentiation h a s not beenvertical at points along the Cordillera.Geographical distributions of any particularspecies are practically impossible to determine withprecision for several reasons. First, because of thehigh elevations and specialized microliabitats inwhich species occur, collections are few and tend tobe concentrated in accessible areas such as R.e.rida


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N U M B E R 43 15(Venezuela), Pichincha (Ecuador), central Per u, an dnorthern Argentina. In addition, and of more seri-ous consequence, trees of most species have beencut by man since prehistoric times for firewood orbuilding materials. Tfith the recent reexpansion ofhuman populations in the high central Andes, cut-ting has accelerated. In contrast to this destructionof natural P oly lep i s populations is the tendency forAndean peoples to p lant or shelter trees near housesor settlements. These two factors combine to pro-duce an apparent distribution pattern that maybear little or no relationship to the original distri-bution of a species. In the mapping of distributio nsin this treatment, I have used specimen and li teraturedata combined with personal observations. Sincemany are old collections (pre-1850), however, cur-rent distributions may now differ from those indi-cated for the various species.

EcologyWitho ut doubt , many species of Polylepis possess

some of the most uniq ue autecological and syne-cological relat ionships of any angiosperm. Whiletaxa that grow at relatively low elevations (e.g.,members of the upper montane forest such asP. m zi l t i j iiga, P . pnz t t a , and P . h i e r o n y m i ) may haveno more specialized adaptations than many othermontane forest trees, those species forming wood-lands at elevations between 4000 and 5200 m mustpossess a suite of specializations th at allow them towithstand the peculiar conditions of these altitudes.In addition to formidable elevations, the highesthabitats also tend to be semiarid since they occuron the western Cordillera of the central Andes,where mean annual rainfall averages between 200and 500 mm. Moreover, tropical areas above 3600 mexhibit extreme variation in diurnal temperatures.Kight temperatures are often below freezingthroughout the year while midday temperatures areoften 10-12C higher. This kind of climatic regimecauses the soil below abou t the top 30 cms to remaina constant 2 4 C (or lower) all year (Walter andhledina, 1969). In addition there is no period dur-ing the year in which plants can become truly dor-mant. Instead, they remain active (some are droughtdeciduous) all year, but under exceedingly harshconditions. Theoretically, the daily freezing tem-peratures, the inability of roots to absorb nutrientsbelow the uppermost soil levels that are heated

dur ing the day, and the presence of a constant, dry-ing wind should preclude tree growth. The occur-rence of woodlands at elevations up to 5200 mtherefore presents a physiological problem. Explana-tions for the distribution patterns of Polylepis havebeen advanced by several workers.

The classic studies of Andean geography are thoseof Carl Troll (see Troll, 1959 for references). Inmany of his expositions, Tro ll specifically discussedPolylepis . In all cases concerning species foundwithin the pu na zone or at the upper limits of theceja (montane cloud forest), Troll considered Poly-lep is woodlands a distinctive type of vegetationdifferent from true ceja, interandean scrub, or punagrassland. The ability of Polylepis to grow abovethe montane forest could, in Trolls opinion, beexplained by the presence of microclimatic phenom-ena that produce lower elevation conditions. Suchphenomena include the formation of cloud layers,especially at night, on some slopes and along lowdrainage areas, which prevent nighttime freezingof th e soil.

In his discussions of Peruvian vegetation, Rau h(1950a,b) also indicated that P oly lep i s grows inspecific elevational belts on west-facing slopes of(primarily) the Eastern Cordillera of Peru. Pulgar(1967) described P oly lep i s as a natural inhabitantof only his siini region. T hi s geographical provinceis confined to eastern and western facing slopesbetwe-n 3500 and 4000 m and contains no large,flat valleys. Tliithiii this zone Polylepis is prevalentalong water courses. While lamenting the fact thatthere is no active reforestation of qz i in iua les (P o ly -Zepis woodlands) where they have been cut, Pulgar(1967:92) cited the custom (almost a superstition)practiced by the Alt iplano Indians of never cut tingdown an old Polylepis tree but merely exploitingthe branches. In his discussion of the p u n u region(defined as the treeless flat plateau at 4000 to 4800m), he mentioned the presence of Polylepis butasserted that individual trees in this zone had beenpurposefully or inadvertently planted by man. Hegave an example of the robust growth of Polylepistrees within the town and arouiitl houses of Cerrode Pasco (Figure Ic) as an example of the former.In the latter case, trees near houses have resultedfrom sprout ing of branches that were brought fromlower regions and which were able to grow Tvhensheltered by huts and walls (Figure I f ) .

In con trast to all of these views is the hypothesis


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16 S M I T H S O X I A S C O N T R I B U T I O N S T O B O T A N Yof Ellenberg (1 958a,b) that the high Andean puna,particularly t hat of the Altiplano of southern Peruand Bolivia, is a manmade grassland which w asoriginally covered by evergreen tree or shrubland.T h e domin ant woody taxa of these natural wood-lands would have been Polylepis , B u d d l e i a , Piiyai ~ z i m o n d i i , nd species of Chi tqz i i raga. T o supportthis hypothesis, Ellenberg first drew a parallel withthe 1fe:literranean region of Europe, which heclaimed has a similar climate to that of the punaand the vegetation of which h a s been shown to havebeen caused by man. He cited examples of Ei tculyp-tz is trees groxving successfully at elevations of about4000 m in the puna. He argued against the restric-tion of Polylepis to slopes with special microclimaticconditions by citing an example of a few trees hesaw growing on a level area . Th e absence of treesanywhere in abundance except on inaccessibleslopes i s attributable, in his opinion, to the cuttingof trees for firewood, the clearing of woodlands forpastureland, and the destruction of seedlings bydomesticated animals in all other areas. He con-sidered the apparent natural and integrated vegeta-tion of the puna simply the result of immigrationand establishment of grasses and forbes from thefew prehuman tree-free areas over the last 40 0 years.

IYhile Ellenbergs hypothesis cannot y e t be dis-proved, i t appears less likely than a hypothesis ofnatural localization of woodlands of Polylepis withan additional reduction due to human influence.A s pointed out by IValter an d hIedina (1969), treeswith a root system over a few centimeters deep can-not normally grow a t very high elevations becauseof the inabil ity of roots to penetrate or absorb waterfrom soil that is between 0 and 4 C . Special situa-tions are necessary to modify the usual prohibitiveconditions. IValter and Jl edi na (1969) proposed thatPolylepis in Venezuela grows in rock areas rvherethe crevices between the rocks allow warm air toreach considerable depths and hence allow rootpenetration and function as low as one meter ormore. Recently, Smith ( 1 977) tested this suggestionby planting seedlings of P. sericea (the nativespecies) in open paramo and sheltered rocky areasat 3600 m in JIerida, Venezuela. Yo seedling sur-vived one year in exposed areas. Seven trees (147,)planted in rocky areas were surviving at the timeof the report (one year af ter planting).

It is obvious that an enormous amou nt of decima-tion and vegetative change has been caused by man

in the high central Andes, but Ellenbergs argu-ments are untenable on several other grounds. Hisexamples are, for the most part, taken from artificialsituations. Eucalyp tus is an introduced genus inSouth America and the trees growing at high eleva-tions have been carefully nurtured and protected.His comparison with the Mediterranean region ismisleading in view of the enormous differences inclimate. Despite the similarities in mean annualrainfall and mean annual temperature (the twoparameters he gives) between the two areas (Walteret al., 1975), the dispersion of the precipitation andthe annual versus diurnal temperature patterns arecompletely d ifferen t. Around the Mediterranean,most of the precipitation falls in the winter and thearea is typically temperate in that summers arewarm and winters cool or cold. In the puna, rainfallis primarily during the southern summer. At anygiven hour of the day a t a locality on the Altiplano,temperature is practically constant throughout theyear, while within any one day there i s as muchas a 12OC temperature difference. Bliss (1956) haspointed out that there are great physiological dif-ferences between arctic and alpine plants (i.e.,latitude and altitude vegetation types with similarphysiognomies), even though they are similar invisual aspect.

Descriptions of many botanists and geographerswho have worked in the Andes (Jameson, 1845;Hertzog, 1923; Weberbauer , 1945; Trol l, 1959;Hueck, 1972) clearly indicate that Polylepis wood-lands are, in the opinions of the authors, a special-ized type of vegetation restricted to certain areassuch a5 rocky slopes, river courses, valley bottoms,or slopes normally covered by cloud banks. Koepcke(1 961) particularly opposed Ellenbergs views. Helogically pointed out that many areas (such as shownin his fig. 59 and in Troll, 1959, figs. 17 and 19) areaccessible to man but still have flourishing Polylepiswoodlands. H e in terpreted the surviL a1 of treesaround houses on the Altiplano not as an indica-tion of their ability to grow naturally at these eleva-tions, but rather as a duplica tion by man of thenormal specialized microhabita t conditions (i.e.,pro-tection from the wind, relatively warm soil condi-tions and, usually, increased water availability) ofareas in which they naturally occur.

T h e only studies tha t shed any light on the pos-sible paleohistory of Polylepis are those of van derHammen and colleagues (van der Hammen, 1974


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N U M B E R 43

and references therein) in Colombia. Because Poly-lepis species are all wind pollinated, pollen coresprovide a comparatively accurate record of theirhistory in a given area. Cores from the Sabana deBogota and Laguna Fuquen, Colombia, spanningalmost three million years provide such a record.T h e core at Bogota clearly shows the first appear-ance of Polylepis in the area at about 600,000 yearsago. Since that time, the fluctuating climates of thePleistocene caused expansions and contractions oflocal Polylepis populations. During a warm wet pe-riod (about 30,000 years ago), the area from whichthe pollen cores were taken was dominated by Poly-lepis woodlands. Shortly afterward, as conditionsbecame colder, low paramo elements became moreabundant until, in drier periods, from 21,000 yearsago, trees were so rare that essentially no grainsappear in the cores. In the latest cores from Fuquen(10,820 Y B P to present), the climate was warmer,but Polylepis never regained dominance, in part,perhaps, because the climate was already dry butalso because of cut ting and bur ning by man. Xever-theless, it is obvious that even at the low elevation(2650 m) of Bogota, the distr ibu tion of Polylepisfluctuated during the Pleistocene and that a com-plete coverage of this high Andean area by wood-lands was an uncommon event and has not occurredsince 30,000 YsP-long before the active influenceof man.

In addition to ecological arguments, i t is hard toexpla in the differentiation of distinct taxa on theEastern and Western Cordilleras as well as north-south along the Andean chain if t here were acontinuous woodland of Polylepis covering themounta ins . Under circumstances of a more or lesscontinuous cover, clinal variation should, at most,develop. However, until the physiology of Polylepisis more completely understood and the microcli-matic conditions of the areas in which it now occursmore thoroughly investigated, the question of thepoten tial distr ibutional limits of the genus will re-main unsettled. In any case, it will be impossibleever to know with certainty the natural prehumandistribution of the genus.

Polylepis Ruiz and PavonPoly l rp is Ruiz atid Pavon, 1794:80 , Icon 15. [Type-species:

Polyl epi s racenosa . ]

17Deciduous or evergreen trees or shrubs, 1-27 m

tall. Bark of the trunk and larger branches deepred, many layered, the layers thin and exfoliating.Branching repeatedly sympodial with long, oftenbare branch segments and leaves slightly to stronglycongested at the tips of branches. Leaves alternate,imparipinnate with 1-9 pairs of leaflets, the first tothe third pair from the apex the largest, rhombic,trull ate or obtrull ate in outline, 0.8-9.1 cm wide,2-19 cm long, rachises sericeous, villous, with scat-tered twisted trichomes, glandular or glabrescent;point of leaflet attachment with a tuft of straightor twisted long trichomes, a ring of glandular tri-chomes, or both; stipules fused around t he branchesforming a sheath; the sheath with spurs on eitherside of, or sloping away from, the petiole, abaxialsurface sericeous, villous, pubescent, glandular orglabrescent, apex with long trichomes often pro-jecting from the inner surface. Leaflets lanceolate,ovate, oblong, or obovate in outline, 0.2-1.7 cmwide, 0.6-3.7 cm long, margins entire, revolute,crenate or serrate, apex acute, obtuse, emarginateor tridentate, base unequally cordate or attenuate;upper surface glabrous, glabrescent, minutely seri-ceous, hispidulous or with scattered niulticellulartrichomes (often most dense in the midvein depres-sion); lower surface sericeous, minutely sericeous,hispidulous, villous, pannose or glandular, oftenwith glandular trichomes mixed with another type,sometimes with a pannose covering under anotherlayer. Inflorescences upright or pendant to 36 cmlong, bearing 1 to over 60 flowers, the flowers closelypacked or spaced along the rachis; floral bractslanceolate to ovate, to 3 mm long, scarious to vari-ously covered with trichomes; raches sericeous, vil-lous, pilose, pannose, glabrescent, or glandular.Flowers perfect (perhaps functionally female insome plant s du e to abor tion of the anthers) , 0.4-1.0cm wide, sepals 3 or 4, lanceolate to ovate in out -line, sericeous, villous, pilose or glandular on theouter face, sometimes pannose on the tips of theinner surface, persistent; stamens (4)) 6-36, basi-fixed, inserted on the floral cup at the base of thestyle; tomentow. or barbate on the anther sacs,longitudinally dehiscent; style villous or hispid atthe base, occasionally villous along most of the style;stigma peltate, o rbicular, flat, expanded, fimbrillate;ovary inferior, rarely protruding from the floralcup; carpel 1, ovule 1, pendulous. Fruit an achene,cylindrical, fusiform, turbinate or globose, variously


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18 S M I T H S O N I A N C O N T R I B U T I O N S TO B O T ANYadorned with protuberances, spines, or wings, bodyand protuberances sericeous, pilose, lanose, villous,with scattered irregular single-celled or multicelledtrichomes, glandular or glabrescent, from 0.2-1.4 cmwide including protuberances, 0.2-1.3 cm long. Seed

pendulous, the testa membraneous and the cotyle-dons flat or slightly convex.

D I S T R I B U T I O N . - h the Andes at elevations of1800-5200 m from Venezuela in the state of Larasouth to Tarapaca, Chile, and Cordoba, Argentina.

Key to the Species of Polyepsis1. Undersurface of leaflets covered with shiny, silky trichomes, the sericeous trichomes some-

times most prominent on the veins: o r covered with dense, straight, short, appressed trichomes,or with long (>2 mm) shaggy trichomes sometimes covering a shorter layer, not glabrous.2. Undersurface of leaflets wi th silky trichomes or short , strai ght, dense, appressed trichomes.

3. Trichomes very silky and covering ent ire under leaf surface, long, dense.4 .4. Pubescence golden red or white; leaflets obovate or broadly oblong: apex

the veins of t he undersurface of leafletsor short , straight, appressed, and overlying a lower layer of very s hort, matted tri-chomes.5 . Lea!.es with 4-9 pairs of leaflets; leaflet$ acute o r ob tuse at the apex, ovate, oblong5 . Leaves with 1-3 pairs of leaflets; leaflets emargina te at the apex , obovate or nar -

rowly oblon g, margins ent ire.6. Undersurface of leaflets dul l with s hort , appressed, straight trichomes over entire

surface and olerlying a layer of sho rt, twisted trichomes; leaflets robust, yellow-ish margins crenate toward the apex; fruit more or less cylindrical with irregu-

6 . P . subsericansarly flattened spines ...............................................................6. Undersurface of leaflets shiny with shor t, silky trichom

on th e veins and leaf margins; leaflets thin, gree n, margins enti re, fruit elongate,2. Undersurface of leaflets with loose, shaggy, lon g (>2 mm) trichomes that can cover

shorter twisted o r multicellular glandular trichomes.7. Leaves with 6-8 pai rs of leaflets: inflorescences 17-36 rm long, flowers numerous,

usually over 20 per inflorescence, densely packed; stipule sheaths strongly spurred ........7. Leaves wi th 3-4 pai rs of leaflets; inflorescences 3-12 cm long , flowers fewer than 20

(occasionally 24) scattered: stipule sheaths lacking true spurs (although trichomes atthe apex can produce t he impression of a poin ted spur).8. Stipule sheaths with prominent long, silky, white trichomes on the outer surface

extending down the internode; leaves with 3-4 pairs of leaflets; undersurface of leaf.lets densely covered with shaggy white scattered trichomes ................3. P. hieronyrni

8. Stipule sheaths sparsely villous on the outer surface and with long twisted trichomesprojecting a t the apex from t he inne r face near th e petiole; leaves with 1-3 pairsof leaflets; un der sur face of leaflets sparsely covered wth shaggy fulvous trichomesoriginating from the veins and with scattered glandular trichomes or protuberances......................................... 14, P . racernosa

I . Undersurface of leaflets covered with 2 mm), twisted, matted, feltlike, whiteor yellowish trichomes or with scatt ered, shor t (


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N U M B E R 4 3 1911.

11.

Upper surface of leaflets very nitid, when young covered with long, shaggy whitetrichomes; stipu le sheaths with acu te spurs, inflorescences 5.8-14 cm long with8-18 flowers; fruits with flattened spines: small trees or shrubs (less tha n 2 m tall)of southern Ecuador and northern Peru ....................................... .9. . weberbaueriUpp er surface of leaflets rugose or slightly niti d, occasionally with scattered l ongtrichomes; young leaflets without conspicuous white trichomes; stipule sheathsobtuse at th e apex ; inflorescences 2.1-5.4 cm long with 3-7 flowers; fruits withthin, terete spines; trees 5-8 m tall of Colombia and Ecuador ....10. P. quudrijuga

9. Undersurface of leaflets with yellow multicellular gland ular trichomes and resinous exudatemixed with short matted trichomes, or glabrous; plants of Ecuador, Peru, Bolivia, orArgentina.12. Undersurface of leaflets glabrous.

13. Fruits s trongly winged, th e wings as wide as the body of the fruit; leaflets broadlylanceolate, almost serrate ...................... 15. P. australis

13. Fruits with irregul ar ridg leaflets obovate or oblong,crenate or entire.14. Fru it wi th irre gular ridges, sometimes flattened in to narrow wings; plantsof Bolivia .......................................................................................... 12. P. tomentella14. Fru it spiny: plants of Colombia, Ecuador or Peru.

15. Apex of leaflets obtus e or acute, iptic to narrowly ovate,..................... 5 . P . sericea15. Apex of leaHets emarginate, leaflet shape broadly ovate, fruits wi th irreg-

12. Undersurface of leaflets with shor t matted trichomes, glandular trichomes, or both.16. Undersurface of leaflets with dense, matted trichomes usually mixed with gland-

ular trichomes most prominent on the veins and leaf margins; plants of southernPeru, Bolivia, northern Chile, and nort hern Argentina.17. Undersurface of leaflets with matted gray or whi te trichomes; sti pu le sheaths

pubescent: fruit with spines prominent at the apex and projected upward,sometimes flattened at the base ............................................................ 11. P. besseri

17. Undersurface of leafiets with a dense covering of mat ted w hite o r yellowishtrichomes; stipule sheaths with glandular trichomes at the apex, glabrousbelow; fruits with short, irregularly positioned blunt spines or blunt spinesflattened and coalesced into a narrow, wavy wing extending the length ofthe fruit .............................................................................................. 12. P . tomentella

16. Undersurface of leaflets with sparse, scattered trichomes an d irregularly scatteredyellow glandular trichomes; plants of Ecuador and central Peru ........13. P. incam

fruits with knobs or stout spines

ular thin spines ........................................................................ 10. P. quadrijuga

1. Polylepis multijuga PilgerPols lepis rr iul t i juga Pilger, 1906:536. [Type collection: at

Chugar near Hualgayoc, Cajamarca, Peru, 2700-3000 m,May 1904, W e b e r b a ue r 4098. Type destroyed, isotypesWRSL, G! ]Trees 4-15 m tall. Leaves only slightly congested

at the ends of the branches (Figure 8a), mparipin-nate with 6-8 pairs of leaflets, obtrul late in outline,6.4-9.1 cm wide, 12.2-19.5 cm long; rachises lanose,point of leaflet att achment (Figure 8c) with a tuftof long, straight trichomes (some with stalked basalcells) mixed with small, clavate, multicellular glan-dular trichomes; stipular sheaths acute at the apexwith spurs reaching 1 cm in length, densely seri-ceous on the outer surface. Leaflets broadly lanceo-late or ovate in outline, second or third pair from

the terminal leaflet the largest, one of this pair1.1-1.7 cm wide and 3.0-3.6 cm long; margins ser-rate; apex acute, base unequally cordate; upper leafsurface sparsely villous in the midvein depression;lower surface densely lanose with individual tri-chomes 1-2 cm long (Figure 8 b ) . Inflorescences pen-dant, 17.3-36.0 cm long, bearing numerous (oftenmore than 45) flowers; floral bracts small, sericeouson the outer surface; rachises sericeous. Flowers per-fect, 0.4-0.8 cm in diameter (Figure 8 4 ; sepals 3or 4, ovate, lanose on the outer surface; stamens5-16, circular in outline, tomentose; style hispid atthe base. Fru it more or less fusiform, sericeous, withirregular spines up to 4mm long (Figure 8e), some-times with long trichomes on the spines, 0.6-1.1 cmwide includ ing spines and 0.3-1.0 cm long.

DIsTRisuTIoN.-Northern Peru in the provinces


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20 S h f I T H S O N I A N C O N T R I B U T I O N S T O B O T A N Y

FIGURES.--Polylepis mul t i jugn: a, branch (X 0.5); 6, undersurface of leaIiet (x 3) ; c, point ofleaflet attachment (X G ) : d , flower (X 6) ; e , fruit (x 6).


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N U M B E R 4 3 21of Amazonas and Cajamarca (Figure 9). Flowersrecorded in May, July, and from September toDecember.COMMOIVAME.-Quinua.

UsEs.-The red heartwood is reported to be usedfor furniture manufacture.

REPRESESTATIVEPECIMESS EXAMINELL-PERU,A M A Z O N A S :Chacapoyas, M a t t h e w s s.n. (K). C A J A M A R A C A :ualgayoc,Hacienda Taulis, 13 km heyond Palmito Juncti on toward LaPlaya, 2900 m , 2 Sep 1964, Hutchison & Bisniark 6463 (F ,MO, SY , P, UC), 3200 m, 15 Oct 1954, Rauh & Hirsch P2249(XY).

DIscussIoN.-In the small restricted area of nor th-ern Peru in which it grows, Polylepis mul t i jugaoccurs as low as 2500 m mixed with species oftree ferns, Podocarpus , Chusquea and Berber is , itsbranches often covered with Til lands ia and epiphy-tic orchids. Bitter considered this species to be themost primitive of the genus. Numerous charactersinvolving morphology, anatomy, and ecology seemto reinforce this conclusion. T he leaves are large,thin, and reminiscent of those of some species ofA c a e n a . The inflorescences are large and pendulous,presumably the ancestral type for the genus. Th e

I ~ U R T .-Collection localities of Poly!epis mul t i juga.

fruits, like those of all of the members of thisspecies group, and species of Acaena , are spiny andappear to be dispersed by animals. More advancedtaxa have become increasingly dependent on windas a dispersal agent. Finally, the species is an in-tegral member of the upper montane rainforest(ceja de la montana), rather than a fringe speciesor one that grows completely isolated from themontane forest in the higher elevations.

The species most similar to Poly lep i s mul t i juga ,P . pau ta , can be distinguished from it by severalleaf characters. Th e leaves of P. mul t i juga are largerthan these of P. pau ta , the lower surfaces are coveredby wooly rather than silky hairs, and the tricliomesat the point of leaflet att achment often have multi-celled bases. In addition, the apices of the stipulesheaths of P. mul t i juga are larger and more roundedthan those of P. pauta and the inflorescences, in thespecimens I have seen, are much larger, both inlength and in the number of flowers they bear. Th isspecies differs from P. lanuginosa in having morenumerous leaflets, obtuse rather than emarginateleaflet apices, and a lanose rather than sericeousunder leaflet covering.

2. Polylepis lanuginosa Humboldt, Bonpland,and Kunth

Polylepis lanuginosa Hurnboldt, Bonpland, and Kunth , 1824:228. [ Type collection: near C alpi, Chimboraz o, Ecuador,June, B o n p l a n d 2191. Holotype P!, isotype P!]Polylepis lehrnannii Hieronymus, 1895:29. [Type collection:west of Cuenca, Azuay, Ecuado r, Leh tnar in 6487. Typedestroyed, Rockefeller photograph no. 3387, types of theBerlin Herbarium, isotypes GH! NY!]

Polylepis coriacea Bitter, 191 h:603. [Type collection: Ialleyof Pangor, Ecuador, Spruce s.72. Holotype I V ! ]Small trees (?) to 4 m tall. Leaves fairly congested

at the ends of the branches, imparipinnate with2-3 pairs of leaflets (Figure IOU ) , obovate in outline,2.9-4.2 cm wide, 4.5-7.2 cm long ; rachises villous;point of leaf attachment with a small tuft oflong straight trichomes; stipular sheath with acute,densely sericeous spurs, the hairs red gold in color.Leaflets (Figure 10a) obovate or oblong in outline,first or second pair from the apex the largest, oneof this pair 0.9-1.4 cm wide, 2.0-3.1 cm long; mar-gins crenate or revolute; apex emarginate; baseunequally cordate, upper leaf surface rugose or dull,sometimes with trichomes scattered in the vein de-


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22 S S II TH S O NI A N C O N T R I B U T I O S S T O B O TA N Y

FIGURE O.--Polylepis lanuginosa: a, b r a n c h (x 0.5); b, l o w e r l e a f l e t s u r f a c e a t p o i n t of leafleta t t a c h m e n t (x 3) ; c, flower (x 6) ; d, f r u i t (x 6).


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N U M B E R 43 23pressions; undersurface densely sericeous, the tri-chomes white or golden red, often with a cover-in g of short wooly trichomes under the silky hairs.Inflorescences (Figure 10a) pendant, sometimesbranched, 0.9-4.4 cm long, bearing 4 to 20 flowers;floral bracts lanceolate, sericeo-lanose; rachises la-nose. Flowers (Figure 1Oc) perfect, about 0.7 mmin diameter, sepals 4, ovate, outer surface villous;stamens about 12, lanose at the apex; base of stylehispid, lower part villous. Fruit (Figure 10d) fusi-form, irregularly spined, the spines flattened or thin,usually villous, b o d y of the fruit pilose; 0.5-0.9 cmwide including spines, 0.3-0.6 cm long.DIsTRIsvTIoN.-Apparently restricted to centraland southern Ecuador in the provinces of Chim-borazo, Azuay, and CaNar (Figure 11). Floweringrecorded April to June.

COMhlON 1\JAME.-QUifiNl.Usm-None specifically reported.

REPRESENTATIVEPECIMENSxAMINED.-ECUADOR. AZUAY:west of Patul , 3 km between Huahualcay and Rio Patulbelow Pasas d e Pinglion, 267CL3275 m, 19 May 1943, Steyer-mark 52599 (F). CARAR: between Tam ho and Suscal, nort hrim of the valley of the Rio de Caniar, 2000-3000 m, 23 Apr1945, Giler 2773 (F , K, NY); Canar, 15 Sep 1918, R ose 6 Rose23789 (NY, S) .

F l C U R r 11 -Collcction local ities of Poly lep is lanuginosa .

DIscvssIoN.-Although similar in many morpho -logical characters and probably derived from Poly-lepis mult i juga, P. lanuginosa differs from it and allother members of the genus in its possession ofbranched inflorescences. In addition to this charac-ter, it differs from P . mul t i juga in leaflet pubes-cence, leaflet shape, and vestiture of the point ofleaf attachment. The leaflets of P. lanuginosa areemarginate, the upper surface is rugose, the lowersurface has a mixture of short wooly trichomes over-lain by dense silky hairs. Leaflets of P. mul t i jugaare acute, the upper surface flat, and the lower sur-face densely lanose. Th e point of leaflet attachmentin the former is a small tuft of straight trichomesand in the latter a ring of glandular hairs mixedwith long st raight trichomes. T h e two species alsohave fruit differences: P. mul t i juga has terete spineson the fruit and P . lanuginosa has flattened spines.

There has been some confusion in the character-ization of this taxon attribu table in pa rt to thespecimens cited by Weddell in the Chlor i s Andina .Weddells brief verbal description could be appliedto many members of the genus, but he cites twospecimens, neither of which belong with the typecited by Humboldt, Bonpland, and Kunth. Wed-dells first specimen was the one he presumablyconsidered the true P . lanuginosa; the secondspecimen corresponds to the variety j3 microphy l la .Bitter correctly realized that neither o f these speci-mens corresponded to the original P. Eanuginosaand consequently made the first specimen the typeof his new species, P. quudr i juga , and the second thetype of P. m icrophyl la . Nevertheless, Weddellsolder application of the name P. lanuginosa wasfollowed by many botanists and has often been mis-applied to specimens of P. quadr i juga or P. weber-bauer i .

3. Polylepis h ieronymi PilgerPoly lep is h i e ronym i Pilger, 1906:535. [Type collection: Salinas,

Cuesta de Pollo, lalle del Tambo, Bolivia, June 1873,L o r e n t z 6 Hie l - o n y mu s 938a . Type destroyed, Rockefellerphot ograph no. 3355, types of the Berlin Herbarium at NY.]

Poly lep is iacemosa p hypoleuca Weddell, 1861:238. [Typecollection: hetween the cities of Tarija and San Luis,Tari ja, Bolivia, Jul-Aug, 1846, W e d d e l l 4607 . Lectotype P!]

Polplepis racemosa var. albotometi te l la 0 . Kuntze, 1898:77.[Type collection: Sierra de Cordoba, Los Gigantes,Gordoba, Argentina, K u r t z 6926. lsotypes S Y ! ]

Poly lep is hypoleuca (Weddell) Ritte r, 191 b :6 0 7 . [Type col-


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24 S M I T H S O N I A N C O N T R I B U T I O N S TO B O T A N Y

FIGURE 2.--Po[ylepis hieronpmi: a, branch (X 0.5); b, uppe r (right) and lower ( left) leaf letsurfaces (x 3) ; c, lower leaf let surlace at point of leaf let attachmeiit (X 6); d , flower (X 6; e,fruit (x 6).


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N U M B E R 43 25lection: based on the same type as P. racemosa p hypoleucaWeddell.]

Polylepis hieronymi var. dol icholopha Bitter, 191 b:609. [Anillegitimate name since it includes the type of the speciesand, under the present Internat ional Code of BotanicalN om enc l a t ure , the correct name must be P . h i e ronym i var.hieronymi .]PolyZepis hieronsmi var. saltensis Bitter, 1911h:609. [Typecollection: near Pampa Grande, the pass El Alizar, Salta,Argen tina, 2400-2600 m, 1900, helson 12584. Holotype S!]Polylepis aus tra l i s var. bijuga Bitt er, 191 1b:624. [An illegiti-mate name, based on the type of P . racemosa var. alboto-mentel la 0 . Kuntze.]Small trees to 3 m tall. Leaves (Figure 12a) con-

gested at the ends of the branches, imparipinnatewith 3 to 4 pairs of leaflets: obtrul late in outline;variable in size, from 1.9-5.2 cm wide and 2.9-9.7cm long; rachises sericeolanose; point of leaflet at-tachment with a band of small, dark-colored multi-cellular glandular trichomes, appearing as a darkring a round the rachis or seemingly undifferentiatedfrom the rest of the rachis but with small glandulartrichomes under the lanose covering, sometimes witha few long trichomes with one or two basal cells:stipular sheaths usually sloping away (downward)from the leaf petiole but sometimes with a slightshoulder, without spurs but sometimes appearingspurred because of the projection of long trichomeson the abaxial surface, sericeous on the outer facewith the long, white silky hai rs sometimes extendingdown the internode. Leaflets (Figure 12a) ovate inoutline, the first pair below the terminal leaflet thelargest, one of this pair 0.5-1.2 cm wide and 1.2-3.2cm long; margins crenate , apex obtuse; base attenu-ate or cordate, the pairs of leaflets often slightly

FIGURE 3.-Collection localities of Polylepis hieronymi .

obliquely positioned so as not to appear paired,terminal leaflet petiolate; upper surfaces (Figure12b) rugose, usually sparsely villous; lower surfaces(Figure 12b) densely lanose with long, twisted tri-chomes. Inflorescences pendant , 4.9-12 cm long,bearing 8-24 flowers; floral bracts conspicuous butsmall, to 1 mm, strigose on the outer surface;rachises tomentose. Flowers (Figure 12d) perfect,0.6-0.9 cm in diameter; sepals 4 (sometimes 3), oval,sericeous on the outer face; stamens 9-13, orbicular ,upper half with a dense beard of straight, yellow orwhite trichomes; stigma spreading; point of styleattachment slightly hispid. Fruit (Figure 12e) almostcylindrical with long, sometimes hooked, spines;body of fruit tomentose, spines occasionally tomen-tose, 0.3-0.9 cm wide including spines, 0.5-1.0 cmlong.

DIsTRIBuTIoN.-SoUthern Bolivia (Tar ija) andnorthern Argentina on the upper slopes of theEastern Andes (Figure 13). Flowering recorded inMarch, June, July, August, and September.

COMMON NAME.-QQuenoa.UsEs.-None specifically repor ted.

REPRESENTATIVEPECIMEXSEXAIfINED.-BOLI\IA. Valledel Tamho, Salinas, 10 Jun 1873, Lorentz L- H i eronym us 93 8(G, NY , S). T A R I J A :OConnor; Quebrada de Canaletas, be-tween Tarija and Entre Rios, 2300 m, 15 Ju1 1954, Meyer18213 (LIL); without precise locality, Mar 1890, B ang 769(F, GH, MO, N Y , US). ARGENTIN4. J U J U Y : EstacionLolcan, Tir ax i, 2300 m, 27 Jan 1927 Casti l lon 38 8 (LIL):T u m b a y a , V o l c a n , 3000 m, 13 Feb 1927, V e n t u r i 9002 (US).SALTA: Dept. Guachipas Pampa Grande, lomas del Zapallar,1810 m, 1 Sep 1949, H ueck 26 0 (LIL).

DIscussIoN.-Collections of Polylepis hieronyrniare scarce despite the statement by Hueck (1972)that this species is a very common tree forming aband of woodlands at the upper reaches of the cejaof the central parts of the Eastern Cordillera. Anexamination of the few available specimens indi -cates that different trees vary in leaf size. The Jujuy,Argentina, specimens I have examined have thesmallest leaves, whereas those from Salta have thelargest.

On the basis of the long, relatively unmatted,cottony pubescence of the under leaflet surface, thepresence of clavate multicellular glandular trich-omes at the point of leaflet attachment, and thelarge, narrowly spined fruits, P. hieronyni i wouldappear to belong to the P. sericea group. Thetwo species, while similar in some respects can, how-


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26 S M I T H S O N IA N C O N T R I B U T I O N S T O B O T A N Yever, easily be told apart. Unlike P . multipora, there rather than straight, spines on the fruit of P. hier-are no spurs on the stipule sheaths of P . hieronymi. onymi seem unique in the genus. Bitter (1911b)The leaves of P . mullijuga also have many more pointed out the similarity of the hooked spines ofpairs of leaflets and there are many more this species to the glochids of some Acaena species,flowers per inflorescence than in P. hjeronymi. Th e bu t it is doubtful if there is any homology in theexceedingly narrow fru it and sometimes hooked, structures. T h e spiny rathe r than alate fruits and

FIGURE 4.--PoZylepis p a u t a : a, branch (X 0.5): b, underleaflet surface (x 2) ; c, point of leafletattachment, upper surface (X 6); d , point of leaflet attachment, lower surface (x 6 ) ; e , flower(X 6 ) ; 1, frui t (X 6 ) .


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N U M B E R 43 27the densely sericeous stipule sheaths distinguish thisspecies from P . besseri and P. racemosa.

4. Poly l ep i s pauta HieronymusPolylepis p a u ta Hieronymus, 1896:313. [Type collection: Cor-

redor Machai, Ecuador, 3900 m, 1871, Stubel 23% Typedestroyed, Rockefeller photograph no. 3390, types of th eBerlin Herbarium at GH , SY.]

Polylepis serrata Pilger, 1906:536. [Type collection: Hua-malics, southeast of Monzon, Huanuco, Per u, 3400-3500 m,1903, We b e r b u u e r 3 3 5 4 . Typ e destroyed, Rockefeller photo-graph no. 3394, types of the Berlin Herbari um at G H, NY,

Polylepis serrntn var. ps i lan thera Bitt er, 1911b:593. [An illegit-imate na me since the original circumscription includes thetype of the species.]

P o l j l e p i s serrnta var. paricipiln Bitt er, 191 1b:593. [Type col-lection: Convencion , Yanam anche, between Cuzco an dSan ta Aria, Cuzcu, Peru, 3500-3800 m, W e b e r b a u e r 4854.Type destroyed, isotype WRSL.]

Poly lep is annula t ip i losa Bitter, 191 b596. [Type collection:Andes of Quito, Pichincha, Ecuador, J am e son 16. LectotypeW!,sotypes G! GH!]Trees ( 2 ) 5-27 m tall. Leaves slightly congested at

the ends of the branches, imparipin nate with 4-9pairs of leaflets (Figure 14a), obt rul late in outline,2.4-6.6 cm wide and 3.4-11.7 cm long; rachiseslanose; poin t of leaflet attachment hispid on theupper surface, the long (to 3 rnm) trichomes (Figure14c) usually mixed with multicellular, glandulartrichomes and resinous exudate; stipula r sheathsred brown, sericeous on the outer face. Leaflets(Figure 14b) ovate, acute at the apex, oblong orlanceolate in outline, second pair from the terminalleaflet usually the largest, one of this pair 0.6-1.4 cmwide and 0.8-3.3 cm long; margins serrate; apexacute; base unequally cordate; upper leaflet surfaceglabrous or slightly tomentose, particularly in themidvein depression; lower surface sericeous with thewhite or gold trichomes completely restricted to, ormost conspicuous on, the veins. Inflorescences pen-dant , 6-21 crn long, bearing 16 to over 60 flowers;floral bracts conspicuous, pilose on the outer sur-faces; rachises sericeous. Flowers (Figure 14e) perfectexcept possibly for some plants from Peru (Cuzco),which appear to be male sterile, 0.3-0.6 cm in diam -eter; sepals 3 or 4, ovate, green, outer surface serice-ous; stamens 5-12, red, sericeous; stigma expanded ,style hispid at the base. Fruit (Figure 14f) irregularlyshapzd, rhomboid to cylindrical with numerous,unequa l, glabrous to villous, th in spines, 0.3-1.4 cmwide includ ing spines, 0.3-1.2 cm long.

U S. ]

DISTRIBUTION.-From north-central Ecuador (P in-chincha) to southern Peru (Cuzco), primarily in theeastern Andes (Figure 15). Flowering an d frui tingrecorded in February, May, July, August, Septem-ber, and December.

COMMON NAMES.-Pauta, quiniual , quena, queuna.UsEs.-None recorded.REPRESE~TATIVEPECIMENSxAhfINED.-ECUADOR. PIAPO:

Mount Guamani, 4000 m, 22 Sep 1939, A s p l u n d 8767 (S).PERU. SANMARTI N: uallaga, Valley of t he Ri o Cipisoncho,30 km above Jucusba mba, io55S, 77OlOW, 3600 m, 22 Aug1965, H a m i l t o n 2 Hol l t gun I 4 9 ( K , S) . Cuzco: Paucartamho,Chacapampa, 1800-2000 m, Dec 1950, no collector 9909 (510);Uruhamba Valley, Torontoy, 1 May 1915, B i n g h a m 55 7 (US);Quispicnachi, Marcapata , 15-16 Feb 1929, W e b e r b a u e r 7803(BM, F, G, GH, K , NY, US); Convencion, Panticalla, 3800m,

revision de la especie polylepis

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