Lichenologist 32(1): 49-55 (2000)Ankle No. lich. 1999.0237Available online at http://www.idealibrary.com on IDEKL

THE LICHENS OF RAROTONGA, COOK ISLANDS,SOUTH PACIFIC OCEAN II: PARMELIACEAE

Simone H. J. J. LOUWHOFF* and John A. ELIX*

Abstract: Ten parmelioid taxa in five genera were identified from Rarotonga, CookIslands, South Pacific Ocean. These comprise: three species of Bulbothrix, onespecies of Canoparmelia, four species of Parmotrema, one species of Rimelia and onespecies of Xanthoparmelia. Canoparmelia rarotongensis Louwhoff & Elix is describedas new, being distinguished from other species of this genus by its unique secondarychemistry (lecanoric acid) and conspicuous, inflated isidia. The majority ofparmelioid lichens on Rarotonga have cosmopolitan and pantropical distributions.Bulboihrix is reported for the first time from the Polynesian region.

© 2000 The British Lichen Society

Introduction

Rarotonga is the largest and the highest (653 m) of the Cook Islands, and issituated between latitudes 2ri2'-15'S and longitudes 159°44'-50'W, in theSouth Pacific Ocean. The island is estimated to be 2 million years old and wasformed during a series of volcanic eruptions (McCormack & Kiinzle 1991).Mueller-Dombois & Fosberg (1998) and Merlin (1985) provided a detaileddiscussion on the vegetation of the Cook Islands. An introduction to thegeology, landforms, vegetation and lichenological history of the island hasbeen provided by McCarthy (2000).

The lichen family Parmeliaceae is well-represented in the SouthernHemisphere, but our knowledge of the distribution of parmelioid lichensacross the Pacific is limited (Elix & McCarthy 1998). About 150 parmelioidtaxa in 25 genera are currently reported for the smaller Pacific Islands (Elix& McCarthy 1998; Louwhoff & Elix 1998). This paper includes a key tothe Parmeliaceae of Rarotonga, brief comments on the species, and adescription of the new species Canoparmelia rarotongensis. As such, it is thefirst comprehensive treatment of the family Parmeliaceae in the region, asonly Parmotrema cristiferum was reported from Rarotonga previously.

Materials and MethodsMore than 150 specimens of Parmeliaceae were collected from a variety of habitats on Rarotongaand were subsequently examined using morphological and chemical characteristics. Chemicalconstituents were identified by thin layer chromatography (Culberson, 1972; Culberson et al.1981; Culberson & Johnson 1982; Elix & Ernst-Russell 1993; Elix et al. 1988), and highperformance liquid chromatography (Feige et al. 1993).

*Chemistry Department, The Faculties, Australian National University, Canberra 0200, A.C.T.,Australia.

0024-2829/00/010049 + 07 $35.00/0 © 2000 The British Lichen Society

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Results

Ten species in five genera were recognized among Rarotongan collections ofParmeliaceae. Parmotrema cristiferum, P. tinctorum and Rimelia reticulata arecommon lichens in many regions of the world and are also widespread acrossthe Pacific (Elix & McCarthy 1998). Parmotrema endosulphureum, Bulbothrixisidiza, B. goebelii and B. tabacina are pantropical species, and their distri-bution in the Pacific region is limited (Elix & McCarthy 1998). The genusBulbothrix has not been encountered previously in the Polynesian region.

Key to the Parmeliaceae of Rarotonga

1 Lower surface erhizinate at lobe margins 2Lower surface rhizinate to lobe margins 6

2(1) Lobes narrow (2-4 mm wide); lower surface with a narrow (upto 10 mm wide), erhizinate marginal zone

Canoparmelia rarotongensisLobes broad (5-20 mm wide); lower surface with a broad (up to

10 mm wide) erhizinate marginal zone 3

3(2) Thallus sorediate; medulla K+yellow then red; salazinic acid presentParmotrema cristiferum

Thallus isidiate; medulla K - ; salazinic acid absent 4

4(3) Medulla pale orange-yellow; C+pink; gyrophoric acid presentParmotrema endosulphureum

Medulla white, C — or C+red; gyrophoric acid absent 5

5(4) Medulla C + red; lecanoric acid present; lobes ± flatParmotrema tinctorum

Medulla C — ; protocetraric acid present; lobes ± foldedParmotrema saccatilobum

6(1) Upper cortex effigurately maculate to reticulately cracked; thallussorediate Rimelia reticulata

U p p e r c o r t e x e m a c u l a t e o r fa in t ly m a c u l a t e ; t h a l l u s i s id ia te . . . 7

7 ( 6 ) C o r t e x K —; u s n i c a c i d p r e s e n t ; l o b e m a r g i n s ec i l i a teXanthoparmelia subramigera

Cortex K+yellow; usnic acid absent; lobe margins with bulbate cilia

8(7) Medulla K — , C+pink; gyrophoric acid presentBulbothrix goebellii

Medulla K+yellow then red; salazinic acid present 9

9(8) Lower cortex black Bulbothrix tabacinaLower cortex pale Bulbothrix isidiza

2000 Rarotonga Parmeliaceae—Louwhoff & Elix 51

The Species

1. Bulbothrix goebelii (Zenker) HaleThis species is finer than either of the other two taxa in this genus described

from Rarotonga, with narrow (0-5-1-5 mm wide) lobes, a black lower cortex,atranorin and chloroatranorin in the cortex, and gyrophoric acid (major) andlecanoric acid (trace) in the medulla. Apothecia and pycnidia not seen but theformer have been reported previously (Elix 1994). Specimens collectedappeared to belong to one of two categories, fine-lobed or broader-lobed.These are not recognized as different taxa and are simply referred to asdifferent morphotypes of B. goebelii. All three Bulbothrix species recognizedfrom Rarotonga are isidiate and pantropical in distribution.

Representative specimens examined (total 14): Cook Islands: Rarotonga: Muri Lagoon, nearmouth of Avana stream, 21°15'S, 159°44'W, 1 m, on trees above beach, 1998, J. A. Elix 42712(CANB); Raemaru Track, 21°14'S, 159°49'W, 100-200 m, in fernland encroaching uponAlbizzia/Allocasuarina forest, on Albizzia, 1998, S. Louwhoff 51 \ (CANB).

2. Bulbothrix isidiza (Nyl.) HaleOnly one specimen of this species was collected on Rarotonga. This species

has atranorin and chloroatranorin in the cortex, salazinic acid (major) andconsalazinic acid (minor) in the medulla, and a pale lower cortex. Apotheciaand pycnidia not seen but reported previously (Elix 1994). In the Pacific it waspreviously reported for the Hawaiian Islands (Elix & McCarthy 1998).

Specimen examined. Cook Islands: Rarotonga: Te Rua Manga Track, climb to the base of TeRua Manga (The Needle), 2 r i 4 ' S , 159°46'W, c. 250 m, corticolous in slope forest with nativetree species Pittosporum and Weinmannia, 1998, S. Louwhoff 615 (CANB).

3. Bulbothrix tabacina (Mont. & Bosch) HaleThis species is characterized by the presence of atranorin and chloroatra-

norin in the cortex, salazinic acid (major) and consalazinic acid (minor) in themedulla, and by the black lower cortex. The latter sets it apart from B. isidiza(see above). Some specimens collected on Rarotonga were broader than usual(10 mm cf. 1-5-5 mm wide) and occasionally displayed marginal lobules.Apothecia not seen but reported previously (Elix 1994). Pycnidia, notpreviously reported (Elix 1994), were observed to be sparse on three speci-mens; conidia rod-shaped to elongate-unciform, (4-5-) 5-7-5 (-8) x 1 \xm.

Representative specimen examined (total 29): Cook Islands: Rarotonga: Raemaru Track, steepslope to summit cliff, 21°13'S, 159°48'W, 200 m, on Paraserianthes falcataria in disturbed forest,1998, S. Louwhoff 563 (CANB).

4. Canoparmelia rarotongensis Louwhoff & Elix, sp. nov.Species cum thallo ut in Canoparmelia owariensis sed ab hac specie thallo corticolo, laxe adnato,isidiis apicibus non erumpentibus et acido lecanorico continente differt.

Typus: Cook Islands, Rarotonga, Muri Lagoon, 21°15'S, 159°44'W, 1 m, on Hibiscus along theforeshore, 6 June 1998, J. A. Elix 42730 (Holotypus—CANB).

(Fig. 1)

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I l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l lFIG. 1. Holotype of Canoparmelia rarotongensis (J. A. Elix 42730 in CANB). Scale in millimetres.

Thallus moderately adnate, membranaceous, up to 6 cm wide. Lobesirregular, ± contiguous and contorted centrally, ± constricted at base ofapices, where lobes become separated, 2-4 mm wide; margins entire, occa-sionally becoming subcrenate, mainly fiat, eciliate. Upper surface pale, dustygrey-green, emaculate, irregularly cracked centrally, isidiate; isidia consist-ently conspicuously inflated, mostly branched, each isidiate cluster up to0-5 mm wide and up to 0-8(-l) mm high, predominantly laminal. Medullawhite. Lower surface black, dull, with a pale brown, narrow (up to 1 mm wide)erhizinate marginal zone; rhizines black, sparse to moderately dense, coarse,simple. Apothecia and pycnidia not seen.

Chemistry. Cortex K+yellow; medulla K - , C + red, PD - ; containingatranorin, chloroatranorin, lecanoric acid (major), orsellinic acid (trace),orcinol (trace). Canoparmelia rarotongensis is known only from the typecollection, where it occurred on Hibiscus in a coastal site.

Notes. The new species is characterized by the conspicuous isidia, which areconsistently inflated, branched, but which do not become sorediate, and bythe presence of atranorin and chloroatranorin in the cortex, and lecanoric acidin the medulla. The new species can be readily distinguished from otherspecies of Canoparmelia by the above characteristics (Elix 1994; Elix et al.

2000 Rarotonga Parmeliaceae—Louwhqff & Elix 53

1986). Lecanoric acid has not previously been detected in this genus. Onlythree species of Canoparmelia, C. caroliniana, C. scrobicularis and C. texana,have been reported for the Pacific region (Elix & McCarthy 1998). The newspecies is morphologically and chemically distinct from these, and has beennamed for its type locality.

5. Parmotrema cristiferum (Taylor) Hale

This species has a cosmopolitan distribution (but is absent from Europe)and is known to be widespread in the Pacific region. Apothecia and pycnidianot seen but the former have been reported previously (Elix 1994). It is amorphologically variable species characterized by sorediate lobes, and by thepresence of atranorin, chloroatranorin, salazinic acid (major), consalazinicacid (minor) and eumitrin Al (trace).

Representative specimen examined (total 19): Cook Islands: Rarotonga: Taputarangi Track, inslope forest, 21°12'S, 159°48'W, 160 m, on twig, 1998, J. A. Elix 42771 (CANB).

6. Parmotrema endosulphureum (Hillm.) Hale

Although Parmotrema endosulphureum has been reported for North, Centraland South America, and for East Africa (Hale 1965), in the Pacific regionit has only been recorded from Fiji (Hale 1965), the Cocos Islands (CostaRica) and the Galapagos Islands (Elix & McCarthy 1998). Parmotremaendosulphureum is isidiate, has atranorin and chloroatranorin in the cortex, andgyrophoric acid and the eumitrin N complex in the medulla, the latter beingresponsible for the pale orange-yellow colouration of the medulla. Apotheciaand pycnidia not seen but the former have been reported previously (Hale1965).

Representative specimen examined (total 2). Cook Islands: Rarotonga: Te Ko'u Track, near taroplantations, 21°13'S, 159°46'W, 100 m, on rock, 1998, J. A. Elix 42822 (CANB).

7. Parmotrema saccatilobum (Taylor) Hale

This species primarily has a South-East Asian distribution, but is alsowidespread across the Pacific, with the type collected from Pitcairn Island. Itis characterized by a large, loosely attached thallus, folded lobes, isidia, and bythe presence of atranorin, chloroatranorin and protocetraric acid. This specieswas morphologically quite variable on Rarotonga. One specimen was observedto produce pycnidia, not previously reported for this species (Elix 1994); theconidia were found to be elongated filiform, 7-12 x 1 urn. One specimen wasfertile, although the spores were slightly longer than usually reported [30 cf.22-26 um (Hale 1965)].

Representative specimen examined (total 13). Cook Islands: Rarotonga: Te Ko'u Track, taroplantations in Takuva'ine Valley, 21°13'S, 159°46'W, 60-100 m, on boulders in disturbedhabitat, 1998, S. Louwhoff 529 (CANB).

8. Parmotrema tinctorum (Despr. ex Nyl.) Hale

This is a cosmopolitan species that is also widespread across the Pacific.Parmotrema tinctorum is morphologically variable, but can be recognized by the

54 THE LICHENOLOGIST Vol. 32

large thallus, isidiate, broad lobes (up to 2-2-5 cm wide), and by the presenceof atranorin, chloroatranorin and lecanoric acid (± traces of orsellinic acidand orcinol). Apothecia and pycnidia not seen but reported previously (Elix1994).

Representative specimen examined (total 40). Cook Islands: Rarotonga: at the mouth of Avanastream, 21°14'S, 159°43'W, 1 m, on seashore trees (Hibiscus and palm), 1998,7. A. Elix 42991(CANB).

9. Rimelia reticulata (Taylor) Hale & A. FletcherA very common, cosmopolitan species, also widely distributed in the

Pacific. Rimelia reticulata is characterized by the emgurately maculate toreticulately-cracked upper cortex, ciliate lobe margins, laciniae with marginalto submarginal soredia, and by the presence of atranorin, chloroatranorin,salazinic acid (major) and consalazinic acid (minor). Apothecia and pycnidianot seen but reported previously (Elix 1994). The species is morphologicallyvariable.

Representative specimen examined (total 23). Cook Islands: Rarotonga: Raemaru Track, cliff-faceat uppermost section, 21°13'S, 159°48'W, 280-360 m, on rock, 1998, 5. Louwhoff 576 (CANB).

10. Xanthoparmelia subramigera (Gyeln.) HaleThis species has been reported as widespread in the tropics, occurring in

Central and South America, South Africa, South-East Asia (Hale 1990) andon islands in the Pacific Ocean (Elix & McCarthy 1998). Xanthoparmeliasubramigera is characterized by the yellow-green, moderately adnate thalluswith subglobose, simple or branched isidia, the pale brown to almost blacklower cortex, and by the presence of usnic acid, fumarprotocetraric acid(major), succinprotocetraric acid (major), protocetraric acid (minor) and± physodalic acid. Although Hale (1990) considered the presence of succin-protocetraric acid as variable, specimens from Rarotonga consistently pro-duced a significant amount of this substance. Apothecia and pycnidia not seenbut reported previously (Hale 1990).

Representative specimen examined (total 6). Cook Islands: Rarotonga: Taputarangi Track,21°12'S, 159°48'W, 160 m, on rock, 1998, J. A. Elix 42760 (CANB).

Patrick McCarthy's company in the field, as well as much appreciated advice on this paper andrelated discussions, are gratefully acknowledged. Thanks are also extended to Gerald McCormackfrom the Cook Islands Natural Heritage Project for accompanying us in the field and providingbackground information; to Judy Wardlaw for assistance with HPLC, to Alex Crathern forassistance with TLC and to the referees for helpful comments. We would also like to thank theAustralian Research Council for their generous financial support.

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Accepted for publication 12 June 1999