fremontia_vol31-no3

F R E M O N T I A 1V O L U M E 3 1 : 3 , J U L Y 2 0 0 3

A JOURNAL OF THE CALIFORNIA NATIVE PLANT SOCIETY

FREMONTIA

$8.00 (Free to Members)

Vol. 31, No. 3 July 2003

IN THIS ISSUE:IN THIS ISSUE:IN THIS ISSUE:IN THIS ISSUE:IN THIS ISSUE:

A CONVERSATION ABOUT MOSSES, LIVERWORTS, AND HORNWORTS by Dan Norris 55555

MOSS GEOGRAPHY AND FLORISTICS IN CALIFORNIA by James R. Shevock 1212121212

THE ROLE OF THE AMATEUR IN BRYOLOGY: TALES OF AN AMATEUR BRYOLOGISTby Kenneth Kellman 2121212121

MOSSES IN THE DESERT? by Lloyd R. Stark 2626262626

THE BIOLOGY OF BRYOPHYTES, WITH SPECIAL REFERENCE TO WATERby Brent D. Mishler 3434343434

SPECIAL ISSUE: BRYOPHYTES

2 F R E M O N T I A V O L U M E 3 1 : 3 , J U L Y 2 0 0 3

The California Native Plant Society(CNPS) is an organization of lay-persons and professionals united by aninterest in the native plants of Cali-fornia and is open to all. Its principalaims are to preserve the native floraand add to the knowledge of membersand the public at large by monitoringrare and endangered plants throughoutthe state; by acting to save endangeredareas through publicity, persuasion,and on occasion, legal action; by pro-viding expert testimony to governmentbodies; and by supporting financiallyand otherwise the establishment ofnative plant preserves. Much of thiswork is done by volunteers throughCNPS Chapters throughout the state.The Societys educational work in-cludes: publication of a quarterly jour-nal, Fremontia, and a quarterly Bulletinwhich gives news and announcementsof Society events and conservationissues. Chapters hold meetings, fieldtrips, and plant and poster sales. Non-members are welcome to attend.

Money is provided through memberdues and funds raised by chapter plantand poster sales. Additional donations,bequests, and memorial gifts fromfriends of the Society can assist greatlyin carrying forward the work of theSociety. Dues and donations are tax-deductible.

Fremontia logo (by L.A. Vorobik) reprintedfrom The Jepson Manual, J. Hickman,Ed., 1993, with permission from theJepson Herbarium, UC. Regents of theUniversity of California.

CALIFORNIA NATIVECALIFORNIA NATIVECALIFORNIA NATIVECALIFORNIA NATIVECALIFORNIA NATIVEPLANT SOCIETYPLANT SOCIETYPLANT SOCIETYPLANT SOCIETYPLANT SOCIETY

Dedicated to the Preservation ofthe California Native Flora

VOL. 31, NO. 3, JULY 2003

FREMONTIAFREMONTIAFREMONTIAFREMONTIAFREMONTIA

Copyright 2003California Native Plant Society

Linda Ann Vorobik, EditorDaniel Norris & James R. Shevock,

Convening EditorsBob Hass, Copy Editor

Beth Hansen-Winter, Designer

CONTACTSCNPS, 2707 K Street, Suite 1Sacramento, CA 95816-5113(916) 447-CNPS (2677)Fax: (916) [email protected]

Sacramento Office Staff:

Executive Director . . . . Pamela C.Muick, PhD

Development Director . . . MichaelTomlinson

Membership Coordinator . . MarinLemieux

Sales Manager . . . . . . . Paul MaasBookkeeper . . . . Lois Cunningham

Fremontia Editor . . . . . Linda AnnVorobik, PhD

Sr. Policy Analyst . . . . . . . EmilyRoberson, PhD

So. California Regional Botanist . . .Ileene Anderson

Rare Plant Botanist . . . Dave TiborVegetation Ecologist . . Julie EvensVegetation Ecologist . . Anne KleinSan Bruno Mtn. Project Coordinator

Mary PetrilliLegislative Advocate .Vern GoehringLegal Advisor . . . . Sandy McCoyWebsite Coordinator . Carol WithamBulletin Editor . Michael Tomlinson

BOARD OF DIRECTORS

Directors:

Carol Baird, Sue Britting, SteveHartman, Lori Hubbart, Lynne Kada,Betsey Landis, David L. Magney,Sandy McCoy, Patt McDaniel, J.Spence McIntyre, Carol Witham

CALIFORNIA NATIVE PLANT SOCIETYCALIFORNIA NATIVE PLANT SOCIETYCALIFORNIA NATIVE PLANT SOCIETYCALIFORNIA NATIVE PLANT SOCIETYCALIFORNIA NATIVE PLANT SOCIETYwww.cnps.org

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CHAPTER COUNCILAlta Peak (Tulare) . . . . Joan StewartBristlecone (Inyo-Mono) . . . . . . . . .

Stephen IngramChannel Islands . . . . . . Lynne KadaDorothy King Young (Mendocino/Sonoma Coast) . . . . . Lori HubbartEast Bay . . . . . . . . . Tony MoroscoEl Dorado . . . . . . . . . Amy HoffmanKern County . . . . . Laura StocktonLos Angeles/Santa Monica Mtns . . .

Betsey LandisMarin County . . . . . . . . Bob SoostMilo Baker (Sonoma County) . . . . .

Reny ParkerMojave Desert . . . . . . Tim ThomasMonterey Bay . Julie Anne DelgadoMount Lassen . . . . . . . . Jim BishopNapa Valley . . . . . . Marcie DannerNorth Coast . . . . . . . Larry LevineNorth San Joaquin . . . . Bob BarzanOrange County . . . Daniel SongsterRedbud (Grass Valley/Auburn) . . . .

Richard HanesRiverside/San Bernardino counties . .

Katie BarrowsSacramento Valley . . Diana HicksonSan Diego . . . . . . Carrie SchneiderSan Gabriel Mtns . . . . Lyn McAfeeSan Luis Obispo . . . . Dirk WaltersSanhedrin (Ukiah) . Chuck WilliamsSanta Clara Valley . . Mary SimpsonSanta Cruz County . Janell HillmanSequoia (Fresno) . . . . Marion OrvisShasta . . . . . . . . . . . Dave DuBoseSierra Foothills (Tuolumne, Cala-veras, Mariposa) . . . . Patrick StoneSouth Coast (Palos Verdes) . . . . . .

Barbara SattlerTahoe . . . . . . . . . . Michael HoganWillis L. Jepson (Solano) . . . . . . .

Mary ShawYerba Buena (San Francisco) . . . . .

Randy Zebell

MATERIALS FOR PUBLICATIONMembers and others are invited to submit material for publication in Fremontia.Instructions for contributors can be found on the CNPS website, www.cnps.org,or can be requested from Fremontia Editor, Linda Ann Vorobik, [email protected], or c/o University and Jepson Herbaria, 1001 Valley Life Sciences Bldg.#2465, University of California, Berkeley, CA 94720-2465.

Prepress by ScanArt / Printed by Craftsman Trade Press


THE COVER: Gametophytes (green haploid generation) of Polytrichum commune, haircap moss. Photograph by M. Hutten.All images in this issue by M. Hutten unless credited otherwise. See this issue in color at www.cnps.org.

CONTENTSGUEST EDITORIALGUEST EDITORIALGUEST EDITORIALGUEST EDITORIALGUEST EDITORIAL ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 44444

A CONVERSATION ABOUT MOSSES, LIVERWORTS, ANDHORNWORTS by Daniel Norris .................................................................... 55555

Through a series of frequently asked questions, Daniel Norris, who taught bryology for years,provides an introduction to the bryophytes (mosses, liverworts, and hornworts), as well asdiscussing some fascinating features of these small green plants.

MOSS GEOGRAPHY AND FLORISTICS IN CALIFORNIAby James R. Shevock .......................................................................................... 1212121212

Be amazed at the great diversity of mosses in California, the habitats in which they grow, andmoss geography, along with a history of moss collecting in California, as you read this articlewritten by one of Californias premier moss authorities. Then consider the fact that mosses newto California, including new species, are continually being discovered.

THE ROLE OF THE AMATEUR IN BRYOLOGY: TALES OF ANAMATEUR BRYOLOGIST by Kenneth Kellman .................................. 2121212121

Experience this journey of a commercial air conditioning mechanic with a fledgling interestin mosses, to an amateur bryologist who is authoring a Catalog of the Mosses of Santa CruzCounty! Ken Kellman shares his joy of learning more about mosses, along with tools,resources, and encouragement for others who may wish to travel this same road.

MOSSES IN THE DESERT? by Lloyd R. Stark .......................................... 2626262626

Most of us think of mosses as being only abundant in wet habitats, festooning trees, or carpetingrocks and logs. In this article the author transforms these stereotypical images by writing of themany mosses of California deserts and where one finds them, along with many fascinatingreproductive strategies employed by mosses surviving in such extreme habitats.

THE BIOLOGY OF BRYOPHYTES, WITH SPECIALREFERENCE TO WATER by Brent D. Mishler ............................... 3434343434

Brent Mishler discusses the evolutionary history of bryophytes, and the physiologicalaspects of these plants that define where and how they live, with particular emphasis onmosses and water.

FROM THE ARCHIVESFROM THE ARCHIVESFROM THE ARCHIVESFROM THE ARCHIVESFROM THE ARCHIVES .............................................................................................................................................................................................................................................................................................................................................................................................................................................. 3939393939

NOTES AND COMMENTSNOTES AND COMMENTSNOTES AND COMMENTSNOTES AND COMMENTSNOTES AND COMMENTS ................................................................................................................................................................................................................................................................................................................................................................................................................ 4040404040

BOOK RBOOK RBOOK RBOOK RBOOK REEEEEVVVVVIIIIIEEEEEWSWSWSWSWS ..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 4141414141

1919191919


GUEST EDITORIAL

have come to increasingly appreciate the abundance of opportunity to ex-

plore and learn from the natural world. Why do I invest so much time and

energy in the study of plants? The answer is quite simple: it is fascinating. I learn

something new almost every day. I cant wait for my next hike where I might

make an acquaintance with a new flower, and now, with each new bryophyte.

Botanical exploration has been both a journey toward intellectual enrichment as

well as my mental health care package. While our lives continue to become

more complex in our high-tech environment, we still have the opportunity to

study nature and be amazed at the infinite ways in which it works. Several col-

leagues have asked me why I became interested in learning about the bryophytes.

The answer is not readily pinpointed, but as the following articles attempt to

convey, the bryophytes are, simply stated, a remarkable group of land plants.

They are worthy of our attention.

When we consider the rate of habitat conversion caused by various land-use

practices, along with the growing population that continually impacts the Cali-

fornia landscape (e.g., urban sprawl), it is more important now than ever that we

have conservation policies that provide for a network of protected areas. The

protected places can (and should) run the full spectrumfrom open space in

urban landscapes to the most remote areas in designated national wilderness

and national parks. All are important and contribute in their own way to species

and habitat conservation. We are truly lucky to live in such a diverse and re-

markable state, and equally fortunate to have no less than 40 percent of our state

in public lands. Few states can boast of such biological diversity as found in

California. However, maintaining this heritage of biodiversity requires aware-

ness, a desire to protect it, and a framework to actually manage for it. The be-

ginning of this process is meaningful and long-lasting change, primarily through

education. Fremontia is one of these educational tools.

As much as we know about the California bryoflora, the process of gather-

ing inventory is still at an early stage compared with that for vascular plants.

Many regions of the state are poorly collected, and our gathering of data about

rare and threatened bryophytes and their habitats is still in the preliminary stages.

Nonetheless, we know that California harbors one of the most exciting and

species-rich bryofloras in the entire country. We are still discovering bryophytes

that are new to sciencecurrently we have more than two dozen in the process

of being described. This indeed inspires us to continue our exploration. I hope

that through this bryophyte issue of Fremontia you may discover a sampling of

what motivates bryologists like me to spend days, months, and years with these

little green plants.

Jim ShevockBristlecone Chapter

Member of the Fremontia Editorial Advisory Board

USEFUL WEBSITESUSEFUL WEBSITESUSEFUL WEBSITESUSEFUL WEBSITESUSEFUL WEBSITESAND CONTACTAND CONTACTAND CONTACTAND CONTACTAND CONTACTINFORMATIONINFORMATIONINFORMATIONINFORMATIONINFORMATION

Bryophyte websites:See Notes and Comments, p. 34

California Native PlantSociety:www.cnps.org, with links toconservation issues, chapters,publications, policy, etc.To sign up for NPCC News,e-mail news on native plantscience and conservation, senda request to [email protected].

For updates on conservationissues:Audubon Society www.audubon.orgCenter for Biological Diversitywww.sw-center.orgNatural Resources DefenseCouncilwww.nrdc.orgSierra Clubwww.sierraclub.orgWilderness Societywww.wilderness.org

For voting information:League of Women Voterswww.lwv.org, includes online voterguide with state-specific nonparti-san election and candidateinformation.

US Senatewww.senate.gov

US House of Representativeswww.house.gov

California State Senatewww.sen.ca.gov

California State Assemblywww.assembly.ca.gov

To write letters:President George W. BushThe White House1600 Pennsylvania Ave. NWWashington, DC 20500

Senator Barbara Boxeror Senator Diane FeinsteinUS SenateWashington, DC 20510

Your CA RepresentativeUS House of RepresentativesWashington, DC 20515

I


A CONVERSATION ABOUT MOSSES,LIVERWORTS, AND HORNWORTS

by Daniel Norris

The moss Mnium spinulosum with gametophyte (leafy lower portion) and sporophyte (stalks and capsules). [See moss life cycle onpage 28.] Note serrated margins toward leaf apex and strong costa (leaf midrib).

any millennia ago, as aMichigan college fresh-man already ten years

into bird-watching, I heard mybotany professor speaking of thejoys of plant collecting. Why wastetime studying plants when beauti-ful birds beckoned? Two years laterin Montana, I watched my pro-fessors wife collecting mosses whileI enjoyed the true excitement ofcollecting beautiful flowers. Now,after 106,000 bryophyte collections,I continue to be obsessed with thebeauty of bryophytes.

Bryophyta (or bryophytes) is thescientific name for a group of plantsincluding the mosses, liverworts, andhornworts. For our purpose, we candefine them as green plants withoutflowers and fruits, and lacking a welldefined system of vascular tissue fortransporting plant fluids through-out the plant. They reproduce, notby seeds, but by single-celled spores.Mosses and most liverworts haveclearly recognizable leaves on clearlyrecognizable stems but they totallylack a root system. All hornwortsand some liverworts lack even a leaf-

stem differentiation but insteadgrow as ribbon-like thalli (singular,thallus). Bryologists typically studyall groups of bryophytes despite thefact that the three groups probablyevolved independently from oneanother. To avoid the more cum-bersome term, bryophytes, I normallyspeak of mosses while meaningmosses, and liverworts and horn-worts as a collective group.

Over the course of my 45 yearsas a bryologist, I have graduallyaccumulated a list of questions thatI might expect from people, who

M


surprisingly want to continue con-versing even after learning of mystrange profession. For example, Iam often asked, Will the densemosses on my apple tree kill it? And Ireply, No, your healthy apple treewill not be hurt by its moss cover.This is because mosses lack a rootsystem, so they simply adhere tothe bark of a tree but do not pen-etrate it.

Only in rare cases will bryo-phytes have adverse effects. In theso-called moss forests of mon-tane tropical rainforests, bryophytesmay become so heavy as to pulldown a branch or even a tree dur-ing heavy rains. Even an apple or-

chard is sparsely covered comparedwith such montane tropicalrainforest trees. There, the trunk,branches, and twigs may be cov-ered to a depth of even a foot ormore, and they may even have densebryophytes on their evergreenleaves. In such conditions theepiphyllous (growing on leaves) bryo-phytes may damage coffee or cocoaby interfering with photosynthesis.

Having dispelled his worriesabout apple trees, my conversantmay next ask about the mosses onhis roof. Yes, they may damage roofsby interfering with drainage. Howdo I combat the moss cover on my roof?Move your house to a more air-pol-

luted area. My facetious answer elic-its questions about bryophytes (andlichens) and air pollution. Withouta root system, all parts of a bryo-phyte plant directly absorb theirwater from raindrops and dew-fall.Unfortunately the water that theyabsorb may contain dissolved sub-stances, including harmful or po-tentially lethal materials from airpollution. Vascular plants are bet-ter protected from such direct airpollution damage. They take innearly all their water via the rootsystem, and those roots have a tis-sue (the endodermis) which excludesharmful materials.

I have heard that lichens are usedin mapping air pollution. Histori-cally, bryophytes and lichens haveboth been used for this purpose.Individual species of bryophytes andlichens differ in response to air pol-lution. Some can be found in highlypolluted areas, and others are killedby even a small amount of air con-tamination. This sensitivity to pol-lution is often a species-specificresponse to levels of mineral ionssuch as chromium, nickel, copper,sulfur, etc. Such species-orientedstudies are more advanced in lichen-ology, and many cities, especially inEurope, produce pollution mapsbased upon the presence or absenceof certain lichen species.

Compared with lichenologicalstudies, bryologists mapping air pol-lution are less concerned with spe-cies distribution around pollutionsources. Instead they focus on min-eral analyses of bryophytes in vari-ous air pollution regimes. Becausemosses absorb all the minerals con-tained in incoming water, scientistsin Europe have been hanging cloth-enclosed bags of mosses from free-way overpasses. Harvest of thesebags at specific intervals is followedby mineral analyses. Interestingly,these studies show recent improve-ment in air quality in most cities innorthern Europe.

Can I clean the mosses from myroof after they are killed by the drought

Clockwise from top: Lophocolea cuspidata. Most leafy liverworts have lobed or dividedleaves, whereas mosses never do. Jungermannia sp., a leafy liverwort, with capsules.Capsules in the leafy liverworts are relatively fragile and short-lived, and are normallydark and spherical. The leafy liverwort Gyrothyra sp. Leafy liverworts appear to haveleaves in two ranks, and unlike mosses, the leaves never have a costa.


of summer? Most mosses are notkilled by drying. Without a rootsystem, mosses must survive dryingrather than merely resisting it.Flowering plants may use the rain-water of last month and even lastyear by continuously tapping theunderground soil reservoir pen-etrated by their roots. Bryophytes,on the other hand, can only use thewater of yesterday and today. Flow-ering plants resist the loss of waterby covering leaves and stems with awaxy covering, the cuticle. Whilebryophytes may have a thin cuticle,it does not protect them from dry-ing. In fact, protection from dryingwould run counter to their need forbeing able to absorb surface water.Because bryophytes must have plantparts capable of rapid water absorp-tion, those same plant parts losewater with equal rapidity.

Species of bryophytes differ inrapidity of water loss and water up-take, and these differences bear closerelationship to the substrate onwhich they grow. Some bryophytesget virtually all of their water fromprecipitation (rain, dew, and mist).This is termed an ecthydric strategy,and the extreme of such a strategy isshown by bryophytes growing onthe extreme branchlets of trees. Incontrast, bryophytes of wet soil orlogs exhibit a more endhydric strat-egy in that they typically take theirwater from the substrate surface andconduct that water throughout theplant in such capillary spaces as thoseformed by the wick of filamentoushairlike processes (rhizoids) on thestem surfaces. These two strategiesare merely polar distinctions; in-be-tween the extremes are innumer-able variations of water uptake de-pending on the substratum.

Easterners have often asked me,Why, in California, are there so manyepiphytic mosses (growing on the trunksof trees)? These epiphytic mossesare, of course, ecthydric, and suchmosses are completely hydrated byonly a few millimeters of rain oreven by water-droplet-laden fog

Conocephalum conicum (top) with sporophytes. The thallus of Conocephalum conicum(bottom left) is several cell layers thick, with air chambers and air pores, as indicatedby the compartmentalization apparent in this image. Ricciocarpus natans (bottomright), a thallose liverwort. The photosynthetic tissue of thallose liverworts is thickened,whereas leafy liverwort leaves are usually one cell thick.


eas of winter maximum rainfall (theMediterranean climate regions ofthe west). In the East, the greatthunderstorms of summer are fol-lowed by a hot drying period whichsoon leaves the mosses no better offthan before the rain. Winters inCalifornia have frequent periods ofsmall and sustained drizzle or mist,and during those winters, the heavymass of epiphytic bryophytes showsmost of its growth.

In vascular plant ecology, wespeak of hydric, mesic, and xeric plantsand plant communities. Such termsdo not work for bryophytes. It isbetter to speak of habitats on thebasis of 1) frequency of hydration/dehydration, 2) duration of hydra-tion, 3) duration of dehydration, and4) intensity of dehydration. Theeastern United States has occasionalshort periods of bryophyte hydra-tion after the rainstorms of the sum-mer, but these are quickly followedby long periods of dehydration be-cause of the temperature of thosesummer months. Winters in mostof the East are characterized by fro-zen conditions without the possi-bility of fluid water necessary forgrowth. In contrast, winters out-side the high mountains of Califor-nia allow for the continuous hydra-tion of the bryophytes, due to thefrequent mists and drizzles and lowevaporation of the cool wintermonths.

Why do mosses grow on the northside of trees? This is not necessarilytrue! Mosses on the north side oftrees do not receive direct sunlightwith its heating and associated dry-ing effects. They may therefore re-main hydrated and photosyntheti-cally active for a longer period oftime. Many trees have abundantbryophytes, not only on their north-ern base but also on all the rest ofthe trunk, limbs and even twigs.The total mass of bryophytes on atree will be reflective of the dura-tion of effective photosynthesis asopposed to the duration of drought-induced dormancy. In more open

forests, the south side of a tree mayeven be limited by temperature ef-fects. Bryophytes are largely cold-weather plants with little or no pho-tosynthetic effectiveness aboveabout 80F.

Why did the moss on the rock inmy front yard die when I sprayed itwith water last summer? Mosses canbe exposed even to the tempera-tures of a Death Valley summer ifthey are dry and dormant. Whenwet and warm, mosses will usuallyuse more food than they manufac-ture, resulting in starvation.

I was skiing the other day andnoticed some thawing patches of snow.Mosses and liverworts were protrud-ing from that snow and apparentlygrowing. How can that be? Mostflowering plants cannot realize anet gain from photosynthesis attemperatures much lower than50F. It is true that some floweringplants can grow through snow, butthat growth involves the use of foodmanufactured and stored the pre-vious year. In contrast, bryophytescan often realize a net gain of pho-tosynthesis at temperatures verynear freezing.

Why are you crawling on the coldwinter ground? My usual answer,I am testing the soil, is the answerof a coward fearful of the recruitersfor the local mental institution. Iam not really crazy. Many mossesand liverworts appear in late falland early winter, and they dry toinvisibility in the summer. Suchbryophytes often grow and com-plete the lifecycle from spore tospore in a period of 610 weeks.They begin growth with the firstmoistening of the soil surface inthe autumn, and they must endgrowth when the grasses begin toshade them in the spring. Califor-nia is a place of great diversity ofthese ephemerals because many ofits regions have winters with un-frozen soil surface left unshaded byvascular plants for several monthsat a time. Northward, there is re-duced duration of such unshaded

Mature hornwort, Anthoceros sp. (top).In this genus the spores are black,as indicated by the dark tips of thesporophytes. Anthoceros sp. (bottom),displaying both developing columnarsporophytes and gametophytes. Thegametophytes of hornworts can bedistinguished from those of thalloseliverworts by their blue-green, greasyappearance.

banks. Most of the eastern UnitedStates contains fewer epiphyticmosses despite generally higher to-tal rainfall. We are contrasting herethe areas of summer maximum rain-fall (eastern United States) with ar-


and moist soil surfaces and withthat reduction we see reduced di-versity of ephemeral bryophytes.

I was in the redwood forests ofnorthwestern California. The broad-leaved trees were drenched with mossesbut the conifers were almost bare.Why? Conifers and angiospermoustrees differ in many respects in thehabitats provided for bryophytes.Conifer bark is typically more acidthan angiosperm bark; it is usuallysomewhat harder; and it continuesto be shaded during the high bryo-phyte growth times of winter.

Perhaps more important is thegreater amount of water and min-eral nutrients provided to the epi-phytes on broad-leaved trees. Co-nifer-branching architecture can belooked upon as an adaptation to thebreakage effects of snow load dueto leaf retention during the winter.

Conifers typically have the branchesangled down from the point of in-sertion on the trunk. Such a patternallows the snow to slide off thebranch tips. Without leaves duringthe winter, most of our broad-leavedtrees can have branches upwardlydirected from their insertion on thetrunk. Such upwardly-directedbranches allow water with containedmineral nutrients to drain down tothe trunk and from there to the soilat the tree base. The bryophytegrowing on a broad-leaved tree thusgets more water and mineral nutri-ents than the one on a conifer. Be-cause it gets more water, it growsmore, and can therefore intercepteven more water and minerals.

Why are you so opposed to peopleearning their living by stripping mossesfrom trunks of trees and selling themfor floral designs? Mosses intercept

the water and minerals that flowdown the trunks of trees. They onlyslowly meter out that material tothe soil where it may be taken upagain by the roots of the trees. Theloss of the moss mat from the trunksof broad-leaved trees means thatthe mineral nutrients enter the soiltoo rapidly, and will therefore belost into the water table and thenceinto the streams. Stripping mossesfrom tree trunks seriously depletesthe fertility of the forest soil.

If all that is true, why isnt thesoil of the coniferous forest rapidly de-pleted of its mineral nutrients? Co-nifers use and lose mineral nutri-ents at a much reduced rate com-pared to broad-leaved trees. Thelow mineral content of waterleached from the canopy of a coni-fer is spread around the forest floorfrom the descending branch tips of

Variation in moss gametophytes (clockwise from top left): Hookeria lucens, recognized by its transparent overlapping leaves. InCalifornia, this moss is the species most likely to be mistaken for a leafy liverwort. Buckiella undulata, a large pleurocarpous mossin California primarily found in the redwood forest zone. Photograph by J. Shevock. Orthotrichum papillosum (with a few sporophytes).Orthotrichum is one of the larger moss genera in the state. Homalothecium sp. This large pleurocarpous moss forms mats on rocksand tree trunks.

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F R E M O N T I A 1 1V O L U M E 3 1 : 3 , J U L Y 2 0 0 3

that conifer. The high mineral con-tent of water leached from thecanopy of a broad-leaved tree isinstead held in the moss mat on thetree trunk. In California those nu-trients are leached out of that mossmat, especially once the rains re-sume in the late fall and winter. Itmight also be noted here that latefall and winter, the time of maxi-mum leaching, coincides with themaximum growth of tree roots.This results in more rapid uptakeboth through the root hairs and bythe fungi that cloak the roots (myc-orrhizae).

One of the most frequent com-ments that I receive on a day ofheavy rain is, A nice day for mossesisnt it? My usual reply of Maybenot! is motivated by studies I con-ducted in an area of temperaterainforests in coastal northern Cali-

fornia. I found maximum epiphyticbryophyte growth on years whenthere was little rainfall in thenormally wet months of Octoberthrough January. Minimum epi-phytic bryophyte growth occurredin times of extremely high late falland early winter precipitation. Thiscounter-intuitive observation seemsto be related to excessive leachingof the epiphytic moss mat with theconsequence of reduced mineralnutrients for growth.

How can I grow bryophytes in myyard? Japanese gardeners are fa-mous for their moss gardens, butsuch gardens are so labor intensiveas to be daunting to a westerner[see Book Reviews, page 41]. Moreappropriate is the growing of mosseson trees or rocks in your yard. Es-pecially with trees, it is often pos-sible to take a large clump of moss

from a tree and to tie it on to thetree with fish line. It is importantthat one take a fairly large patchbecause mosses operate on what Icall a Catch-22. They can surviveif there are enough of them to in-tercept and hold sufficient waterduring a dry time. In nature, onewonders how they get from beingsmall and easily dried to becominglarge and less easily dried.

Another approach to plantingbryophytes, and one that works es-pecially well on rocks, is the use ofplant fragments. Any living cell ofalmost any bryophyte has the po-tential to grow into a mature plant.A bryophyte can grow from frag-ments processed in a blender andsprayed onto a suitable surface. But-termilk is often included in theblender brew to provide a suitablyacid glue for these fragments.

Can I simply take the spores froma moss capsule and tap them out onto asuitable surface? Probably not. Mostbryophytes reproduce primarilyfrom plant fragmentswhetherfrom the dirty toenails of squirrelsor the dried materials adhering to aducks legs. Sporic reproductionseems to primarily be an adaptationto very occasional long-distance dis-persal, something that is probablynot very common. Experimentalwork in The Netherlands has shownthat most bryophyte spores diedwhen exposed on the wings of air-lines for even a single transatlanticflight.

As you might now more fullyappreciate, bryophytes are a fasci-nating group fully justifying my life-long obsession. There is enoughyet to be learned about these plantsto justify an obsession of a similarlength, or a passion equaling mine,for a few tens of thousands of ap-propriately curious amateur or pro-fessional bryologists.

Dan Norris, University Herbarium, 1001Valley Life Sciences Bldg., No. 2465, Uni-versity of California, Berkeley, CA 94720-2465. [email protected]

Variation in moss sporophytes: Opposite page, clockwise from top left: Buxbaumiaviridis. Species in this genus are called bug on a stick! Buxbaumia is unique in thatyou only see the plant when sporophytes are present because the gametophytes are soinconspicuous. Trachybryum megaptilum. This moss and other pleurocarpous mosseshave capsules attached on lateral stems, as opposed to acrocarpous mosses, with capsulesattached at the tips of the stems. Scouleria aquatica. At maturity, the capsules of thismoss turn chestnut brown, and are shaped like an inner-tube. It is found seasonallysubmerged in rivers and fast flowing streams; when dessicated, the plants turn jet black. Polytrichum juniperinum, called the haircap moss for the netted coverings (calyptra)over the capsules. Philonotis fontana is named the green apple moss, for its sphericalcapsules. Primarily found in springs and seeps. Photograph by J. Shevock. Neckeradouglasii. In California, this epiphyte is found in the coastal rainforest. Note the penduloussporophytes and ring of appendages (peristome teeth) at the mouth of the capsules.This page, left to right: Sphagnum sp. Members of this family (Sphagnaceae) are uniqueamong mosses: sporophytes lack peristome teeth and the leaves contain water-holdingcells and lack chlorophyll. Heterocladium macounii. Note the peristome teeth.


MOSS GEOGRAPHY AND FLORISTICSIN CALIFORNIA

by James R. Shevock

osses are the largest of thethree lineages of bryo-phytes. With nearly 1,200

species of mosses recorded forNorth America, California hasnearly half of them. So what ac-counts for this great diversity ofmosses within the state? Californiais well known throughout the worldfor its vascular flora, a flora influ-enced and evolved in relation to a

Mediterranean climate. Only fiveregions in the world have such aclimatic pattern of cool wet wintersfollowed by long hot and dry sum-mers. The Mediterranean climateis the defining factor in explainingthe species rich moss flora in Cali-fornia as well.

Then why do plant enthusiastsand professional botanists generallyknow so little about the mosses?

The best answer seems to be thatmosses are just the wrong size andhave little or no recognized eco-nomic value when compared to theflowering plants. Our smallest mossin California is probably Ephemerumserratum that forms a green fila-mentous growth on soil after thewinter rains. The capsules of Ephe-merum are around 0.25 millimeterin diameter. The other size extreme

Sphagnum girgensohnii. Most people have heard of peat moss, which is the common name for members of the genus Sphagnum.Although peat moss covers large expanses of the northern hemisphere, and is ecologically one of the most important groups ofmosses in the world, it is relatively uncommon and relictual in California.

M


is found in the genus Fontinalis, thewater mosses, with plants up to onemeter in length.

Mosses are perceived to be hardto identify, have no showy featureslike flowers, and are just overlookedby many of us. But upon closer ob-servation of our environment,mosses are actually all around us ifwe take a moment and focus ourattention at a different scale. Viewedthrough a hand lens or microscope,mosses are simply stunning [For anintroductory article to this group,see Fremontia 26(2): 38, 1998, sum-marized on page 39 of this issue].Mosses are no more difficult to learnand identify than vascular plants oncesome basic new terminology andmicroscope techniques are learned.

The major difference betweenmosses and vascular plants is thatidentifying most mosses to the spe-cies level generally will requiregreater magnification than can beobtained with a hand lens alone.Another reason why the mosses ap-pear to be overlooked seems to bethat botanists have placed an inor-dinate amount of value on beingvascular at the expense of the rest ofthe plant kingdom. The result ofthis is that all of the plants andplant-like organisms without vas-cular tissue are often simply lumpedin botany textbooks as non-vascu-lar plants, or cryptogams.

We now recognize and acknowl-edge that mosses actually play a keyrole in ecosystem function, espe-cially how they regulate the releaseof water and assist in protecting soilfrom erosion. Mosses can also tellus much about climate change. Thisis why the California Native PlantSociety (CNPS) and botanists affili-ated with land management agen-cies are looking at the mosses in anew conservation light. To learnmore about mosses from a non-tech-nical approach, I highly recommendthe recently published book Gath-ering Moss, a Natural and CulturalHistory of the Mosses by RobinKimmerer. [See review on page 41.]

Mosses can grow on surfacesthat are generally not available tovascular plants. Mosses are also ex-tremely important as pioneeringspecies as they can cover bare ex-posed soil caused by fire, landslides,or other perturbations. Even in ur-ban centers, mosses can grow onthe sides of buildings, on concreteretaining walls, and even asphaltwalkways!

Mosses use a different strategyto regulate water loss than do vas-cular plants. Since they lack roots,they are not restricted to growingon soil. Many mosses are quite

content to grow on rock surfaces,such as members of the genusGrimmia with over 30 of the 75species world-wide residing in Cali-fornia. Grimmia species can befound in every county of the state.Other mosses prefer tree bark, andas a general rule, favor hardwoodtrees over conifers. Bark character-istics like chemical composition, tex-ture, and water-holding capacity areimportant in moss colonization ofthis particular habitat. Mosses oc-curring as epiphytes on tree barkand branches do not adversely af-fect the trees. In fact, mosses have

Dendroalsia abietana (when dry, below left), a species endemic to western North America,is a large moss, and especially common in the foothill woodland. When dry, the stemscurl, similar to a fern frond or the head of a violin. Dendroalsia abietana (when moist,below right) with capsules arising from the underside of the branches. Photographs byJ. Shevock.

Ephemerum serratum (above left) is perhaps the smallest moss in the state of California,with capsules smaller than a pinhead, and is seen only during the winter months inwestern North America. It is found on soil. Photograph by J. Game. Fontinalis gigan-tea (above right), commonly called the water moss. Plants are generally found submergedin streams and rivers, and can reach one meter in length.


exploited just about every ecosys-tem in California from sea level tothe summit of Mt. Whitney, fromareas receiving barely an inch ofwater a year in parts of Death Val-ley to the temperate rain forestsdominated by coast redwoods.

Of course the lack of both iden-tification field guides or an illus-trated moss flora for California hasnot made it easy for plant conserva-tionists, enthusiasts, or professionalbotanists to learn about the mosses.However, plans are underway toprovide such publications for ourstate. Currently one has to use avariety of regional moss floras inthe United States to aid in mossidentifications. Lawton (1971) andFlowers (1973) are the two mostimportant moss floras available forCalifornia botanists. Dan Norris andthis author have a catalogue of Cali-fornia mosses and a key to speciesready for publication in Madroo thatis due to be published in early 2004.

HISTORY OF MOSSHISTORY OF MOSSHISTORY OF MOSSHISTORY OF MOSSHISTORY OF MOSSCOLLECTING INCOLLECTING INCOLLECTING INCOLLECTING INCOLLECTING INCALIFORNIACALIFORNIACALIFORNIACALIFORNIACALIFORNIA

Many of the great botanical ex-plorers of the 1800s in Californiawere also involved in the collection

of mosses. The botanists Bolander,Brewer, Bigelow, and Coville haveall contributed to this effort. In fact,Bolander was the principal collec-tor of mosses during the 1860s, andmany mosses new to science weresubsequently named for him tocommemorate his efforts. In the1900s, other botanists collectedmosses in California, too. Leo Kochand Fay MacFadden were the twoprominent bryologists who addedmany moss collections to herbariain the 1950s. MacFadden was onstaff at Fullerton College, whileKoch taught at Bakersfield College,Tulane University, and then at Illi-nois. In 1950 Koch published hislist of California mosses in Leafletsof Western Botany, just after com-pleting his PhD on the distributionof California mosses while at theUniversity of Michigan.

Other nationally known bry-ologists during this era came out ofStanford. William Campbell Steerespent much of his professional ca-reer at the New York BotanicalGarden, and Wilfred Schofieldtrained many bryologists whileteaching at the University of Brit-ish Columbia, Vancouver. WilfsIntroduction to Bryology textbook hasrecently been reprinted in a paper-back edition (available at www.

blackburnpress.com) and will be ofconsiderable interest to those want-ing to learn more about this fasci-nating group of plants. In addition,another great book to begin a studyof bryophytes is Structural Diversityof Bryophytes by the late HowardCrum. It can be ordered from theherbarium at the University ofMichigan, Ann Arbor.

During the past 30 years or sothe indefatigable bryophyte collec-tor Dan Norris has nearly doubledthe number of mosses recordedfrom the state since Kochs list.Dans collections, numbering over106,000, come from all corners ofthe globe and are permanentlyhoused at the University of Cali-fornia, Berkeley. Probably manyCNPS readers are not aware thatprominent botanists such as AliceEastwood, John Thomas Howell,Willis Linn Jepson, Philip Munz,

Meesia triquetra (below top), a relativelyrare moss in California, found in Sierranfens. Photograph by J. Shevock. Close-up of Meesia triquetra (below bottom),showing the three-ranked leaves, as thespecific epithet implies. Photograph byJ. Game.

Ptychomitrium gardneri, an acrocarpous moss, found on rock. This is one of the fewmosses with several sporophytes arising from a single sexual bud (perichaetium).Photograph by J. Shevock.


Peter Raven, Ledyard Stebbins, andLouis C. Wheeler collected mossesamong their flowering plant work.However, their moss collectionswere generally few in number. Be-sides these prominent botanists,several moss floras at either countylevel or other administrative unitswere developed as part of masterstheses at the state universities atHumboldt, Pomona, and San Fran-cisco during the 1970s and early1980s.

Amateurs and botanists work-ing within the land managementagencies are primarily responsiblefor the current interest in the studyof California bryophytes. Rarity andconservation of bryophytes are nowbeing included as components oflarge landscape management strat-egies to provide for biodiversity atvarious scales in both the PacificNorthwest and in the Sierra Ne-vada. The Northwest Forest Plan,a major Environmental ImpactStatement planning document es-tablished in the 1990s within thespecies range of the northern spot-ted owl, specifically requires sur-veys for cryptogams thought to berare and restricted to old growthforests. These survey requirementsfacilitated a need for botanists toexpand their scope of knowledge toinclude the identification of and sur-vey protocols for bryophytes as wellas other cryptogams.

Top to bottom: Andreaea rupestris.Members of this genus are commonlycalled the granite mosses, and are re-stricted to acidic rock types. The capsuleson Andreaea are unique: note the foursplits on the burgundy-colored capsule.In the field, the whole plants are usuallyabout the size of a human thumbnail. Aulacomium androgynum is a commonspecies on logs and rotting wood. Notethe spherical gemmae which are asexualreproductive structures, that are, simplyspeaking, a whorl of modified moss leaves. Schistidium rivulare always occurs onrock, usually on seasonally wet areas suchas boulders along a stream, or rocks ofintermittent streamlets. The peristometeeth of the capsules are bright red toorange.


MOSS FLORISTICSMOSS FLORISTICSMOSS FLORISTICSMOSS FLORISTICSMOSS FLORISTICS

While California lacks an illus-trated moss flora, moss floras andchecklists have been produced forthe state going back to the 1860s.Leo Lesquereux presented the firstpaper on California mosses to theAmerican Philosophical Society in1863, and in 1868 the CaliforniaAcademy of Sciences published hisMosses From the Pacific Coast of NorthAmerica. Mosses documented fromCalifornia were prominently refer-enced in that work. Again, it wasthe moss specimens acquired byBolander that contributed most tothis undertaking.

In 1880, the second volume ofthe Botany of California edited bySereno Watson was published, andit now included the mosses. Thiswas the first flora to address all ofthe mosses recorded or presumed tooccur in California at that time. Thismoss flora documented 181 mossesfor California. By the time of Koch(1950) the number of mosses docu-mented for California had nearlydoubled to 317. A new catalogue ofCalifornia mosses referenced earlierby Dan Norris and this author willnearly double the number of mossesdocumented for California since theKoch publication.

While mosses have been re-corded for each of the 58 countiesin California, some portions of thestate have been more systematicallysampled. In part, this reflects thelocation of educational institutionswhere bryology was taught in thepast. The coast redwood forest re-gion and adjacent coastal environ-ments from Santa Cruz Countynorth through Del Norte Countyhave been fairly well sampled whencompared to other regions of thestate. Moss catalogues, checklists,or floras have either been devel-oped or are in preparation for DelNorte, Lake, Marin, San Francisco,and Santa Cruz counties. The mas-ters theses produced at Cal PolyPomona in the 1970s focused on

Clockwise from top left: Hylocomium splendens, called the stair-step moss. Althoughabundant as a forest floor covering in North America, it is rare in California, restrictedto the California-Oregon border. Photograph by J. Shevock. Buxbaumia piperi, aspecies seen only when sporophytes are present. Buxbaumia is generally found on logs,and occurs in the northwest corner of California. Note the extension of the peristometeeth. Photograph by J. Game. Racomitrium varium, commonly found on coastalrocks. The whitish tips (hyaline awns) of the leaves give this moss a frosted appearancewhen dry. Photograph by J. Game. Sphagnum capillifolium. This Sphagnum species,although rare in California, is very distinctive due its reddish-tinged hue.


other types of landscape units suchas mountain ranges or wildernessareas within southern California.

But with the demise of manyfield-oriented university biologyprograms in the 1990s, all of thecampuses that once taught bryol-ogy in California have ceased tooffer such training and education.It is through the efforts of DanNorris as well as the Jepson Work-shop Series [see page 40] that cur-rent taxonomic training in bryol-ogy is being provided, much of thistraining directed to expanding theskills of amateur and professionalbotanists, especially those employedwith land management institutions.

MOSS GEOGRAPHYMOSS GEOGRAPHYMOSS GEOGRAPHYMOSS GEOGRAPHYMOSS GEOGRAPHY

Much has been written aboutthe California Floristic Province,an area not confined to the stateboundary but excluding the GreatBasin and Desert regions. The Cali-fornia Floristic Province extendsnorthward into Southern Oregonnear the Medford and Grants Passregion, and southward to the north-ern portion of Baja CaliforniaNorte, Mexico. As already noted,winter precipitation is a key featureof a Mediterranean climate, and therainfall increases northward andwestward across the California Flo-ristic Province.

Beyond the California FloristicProvince, the eastern portion ofCalifornia is influenced by the GreatBasin Floristic Province dominatedby sagebrush and pinyon pine-juni-per woodlands that are well repre-sented in Modoc and Mono coun-ties. This last region includes theColorado and Mojave deserts, andis dominated by creosote bush scrubin portions of Inyo, Imperial, Riv-erside, and San Bernardino coun-ties. Therefore, it is fairly easy todescribe the pattern of moss distri-butions in the state by reviewingthe annual amount of precipitationeach area receives.

In all of Californias deserts rain-fall is considerably reduced, anddesiccation tolerance of mosses be-comes a more important factor,along with growth form, in under-standing species distribution pat-terns. Mosses in the familiesPottiaceae and Grimmiaceae, withdense cushion growth forms(acrocarpous mosses), are dominantin arid environments, whereasmosses that have a matted, pros-trate and highly branched growthform (pleurocarpous mosses) areindeed uncommon in the deserts.

Some of the desert mosses oc-curring in California also occur inother desert regions around theworld. In many cases, it is the samespecies, or a sister species occupy-ing the same basic ecological niche.As one would expect, there arefewer mosses in the dry interior ofthe state than in the coastal coun-ties. [See articles in this issue byLloyd Stark and Daniel Norris formore details.]

Climate and precipitation arethe primary factors influencing spe-cies distributions. For mosses, therecurring interval pattern betweencell saturation and desiccation setsthe ecological tolerances for manymoss species. Once cells are satu-rated, mosses have no ability to storeadditional water. Some mosses needto be wet or moist most of the year,such as species in springs and mead-ows or along rivers and creeks wherethey are seasonally submerged dur-ing peak flows.

Secondary factors influencingspecies distributions include sub-strate availability and elevation.Mosses occur in California from sealevel to over 14,000 feet. Some spe-cies are relatively common suchas Bryum argenteum and Funariahygrometrica which have very widehabitat parameters and can be lo-cated throughout California. Oth-ers, however, are very specific tomicro-environments. Some mossesprefer particular rock chemistry,such as acid rocks like granitics,

while other species prefer a higherpH like carbonate rock types in-cluding marbles and limestones.

Perhaps the mosses most re-stricted by substrate specificity arethe copper mosses. Both Mielich-hoferia elongata and Schizymeniumshevockii are restricted to rock typeswith high concentrations of met-als like copper and are primarilylocated within the foothill wood-land areas. Scopelophila cataractae inCalifornia has only been collectedonce in the Copperopolis area inCalaveras County. Pseudoleskeellaserpentinensis, as the species nameindicates, is restricted to serpentineareas in northern California.

Other mosses like to occur alongrocky intermittent streamlets androck slabs with little competition.Mosses preferring this type of habi-tat include Didymodon norrisii andSchistidium spp. Some mosses arenearly exclusively aquatic such asmembers of the genera Fontinalis,Hygrohypnum, and Scouleria, exposedonly during low flows of unpollutedrivers and streams. Although thereare no marine mosses, some specieslike Schistidium maritimum can tol-erate salt spray. Schistidium mari-timum occurs from MendocinoCounty northward. Only a handfulof mosses can adapt to alkaline soilsthat contain a high accumulation ofsalts.

Within the California FloristicProvince, the distribution patternof many mosses follows a generalpattern that is observed in the flow-ering plants. Common mosses inthe coastal northwest portion ofthe state become increasingly un-common southward, making theirsouthern limit in the northern Si-erra. Many mosses of the coastalcounties such as Alsia californica,Bryolawtonia vancouverensis, andTriquetrella californica are not lo-cated inland, just as many of themosses located in the alpine zone ofthe Sierra Nevada are not foundelsewhere in the state.

Two regions of the state are


noteworthy for the amount of mossbiomass occurring in the ecosys-tem. The first is the area domi-nated by the coast redwood forests.Epiphytic masses of Isotheciummyosuroides and liverworts drapefrom the branches of trees, forminga tapestry of pastel greens while theforest floor is carpeted with mosses.The second area where moss coveris abundant is along the foothills of

the Sierra Nevada between the blueoak and black oak zone, especiallyalong the river canyons. Here manyspecies of mosses carpet tree trunksand boulders, such as Antitrichia cali-fornica, Dendroalsia abietina, andHomalothecium spp. In both cases,these areas are basically snow-freealthough snows may linger for afew days after major storms. Growthcan occur once plants are hydrated

after the first rains in the fall andcan continue to grow until the lastrains in May.

The moss flora of California isalso interesting when compared withthe moss floras of adjacent states.Only about 50% of the mosses re-corded for Arizona also occur inCalifornia. As with the floweringplants, water availability and climateplay a key role in species distribu-tions. The distribution of many mossspecies that occur in Arizona butnot in California can be attributedto the availability of summer rain.In California, mosses are basicallydormant in the summer, yet in muchof Arizona, growth can occur in thesummer due to that states mon-soon rainy season. Because of thisclimatic feature, the moss flora ofArizona has greater affinities withMexico and the eastern UnitedStates than it has with neighboringCalifornia. For the most part, onlythe mosses of the Mojave and Colo-rado deserts have distributionswhich overlap both states.

The state of Nevada is lessknown bryologically, but it has manymosses in the high mountain rangesthat have greater affinities to themoss flora of the Rocky Mountains.In the Great Basin Floristic Prov-ince, winter growth is limited dueto snow, and the region does re-ceive some summer precipitationand this in part accounts for thesedifferences. Even Oregon, once be-yond the northernmost section ofthe California Floristic Province, hasa different moss flora. There are atleast 70 species of mosses in Or-egon which have not been docu-mented to occur in California. Thesespecies are more aligned to taxafound in British Columbia andAlaska, and most are generallypleurocarpous mosses. Several of thelarge and dominant mosses on theforest floor in much of westernNorth America such as Pleuroziumschreberi have not been found in Cali-fornia. Hylocomium spendens, perhapsthe most common pleurocarpous

Schistostega pennata (top), commonly called the goblin moss. While not yet found inCalifornia, this very small (less than 1 cm) but distinctive moss should be found inareas with windthrow (exposed rootballs) and in openings of rock recesses, such as acave. The nearest location is in southwestern Oregon. Pleurozium schreberi (bottom),commonly called red-stem, is one of the most common feather mosses (i.e., pleuro-carpous mosses) of North America. However it is yet to be found in northern Cali-fornia, where it should occur.


moss species in North America, hasonly been recorded three times inCalifornia, and then only along theOregon border.

Distributions of large moss gen-era are a fascinating study here inCalifornia too. The genus Raco-mitrium and Sphagnum offer twogreat examples on species distribu-tion patterns. Mosses in the genusRacomitrium, with nearly 100 spe-cies worldwide, generally inhabitrocky substrates. This genus is wellrepresented in North America.With 18 species of Racomitrium forCalifornia, we see a rapid decreasein the number of species as oneleaves the northwest corner of Cali-fornia and the northern Sierra. Bythe time one arrives at the southernSierra, over half of the Racomitriumspecies have dropped out. This ge-nus is totally absent from mountainranges in the Mojave Desert and israre in southern California.

Peat mosses in the genus Sphag-num offer a different distributionpattern in California. There areabout 200 species of Sphagnum inthe world and they are common inhigher latitudes, especially in theNorthern Hemisphere. The 23 spe-cies of Sphagnum in California arerestricted to bogs or perennially wetmeadows and fens and are distrib-uted in two distinct patterns. Spe-cies of Sphagnum from the firstgroup are coastal, found along la-goons or in areas with poor waterdrainage among the coast redwoodbelt in northeast California, withthe greatest species diversity occur-ring at the pygmy forest region nearFort Bragg in Mendocino County.

Sphagnum species from the othergroup are montane and are concen-trated in the Sierra Nevada in mead-ows, fens, and lake shore habitats,from the lodgepole pine forestsup to the alpine zone, generally inassociation with blueberry (Vacci-nium), labrador tea (Ledum), Kalmia,and sundew (Drosera). By the timeone gets to Tulare County, only ahandful of Sphagnum species re-

main, and no Sphagnum have beendocumented from any of the moun-tain ranges of southern California.Perhaps the most remarkable sta-tion for Sphagnum in California isrestricted to a small wet meadowsurrounded by a pinyon pine wood-land near Bodie, Mono County.Clearly this is a relictual occurrence,a holdover from the Pleistocenewith no suitable habitat for miles inall directions. The nearest occur-rence of a Sphagnum species to thissite is nearly 4,000 feet higher upalong the Sierran crest.

Because mosses generally havemuch larger geographical distribu-tions than vascular plants, the num-ber of mosses endemic to Califor-nia is therefore reduced. What wehave instead is a distribution pat-tern of widely-spaced disjunct oc-currences. Many mosses are re-corded from California from onlyfive to ten occurrences. In somecases, this is merely a reflection ofthe number of herbarium specimensavailable for study and the collect-ing habits of botanists, yet othermosses are indeed very rare in Cali-fornia. Some mosses in Californiamust now be viewed as relictual spe-ciesholdovers from a different cli-

matic era. Atractylocarpus flagellaceusand Campylopodiella stenocarpa aretwo such species that have recentlybeen documented for California and

Tetraphis geniculata (below top), is namedfor the bent stalk (seta) of the sporophyte.Although reported for California, aspecimen of this species has not beenconfirmed. Its sister species, T. pellucida,is fairly common in northwest California,especially in the northwests redwoodforest. This is the only moss in Californiawith four peristome teeth. Tayloria sp.(below bottom) is a member of the dungmoss family (Splachnaceae). Currentlythis family has not been found in Cali-fornia, even though Tayloria serrataoccurs as close as southern Oregon (nearCrater Lake).


are distant disjuncts from centralMexico.

The greatest threat to mosses inCalifornia is not species extinction,but rather, the loss of unique andhighly isolated occurrences. Theseisolated and small populations areconsiderably more vulnerable to lo-

calized extirpations by alteration ofhabitat or loss of their specific mi-cro-environments. In many cases,natural recolonization from suchlosses would be extremely unlikelybecause available spore or plantfragments are so far away. In nearlyany study area for mosses in Cali-fornia, a suite of mosses will berare for that location.

While California has nearly 600mosses documented to date, theyare not evenly distributed amongthe 58 counties in the state. Over300 mosses have been recorded forthe southern Sierra, and even oursmallest county, San FranciscoCounty, has a moss flora of over130 species. Probably the countywith the richest moss flora will turnout to be Siskiyou County, but acomplete species list is not currentlyavailable. There are probably onlyabout 100 mosses for the entireMojave Desert, yet this is the leastknown area bryologically in Cali-fornia, so our knowledge of thisportion of the state is bound tochange once more bryophyte col-lections are made.

Therefore, the current pictureof the mosses in California is one ofa highly species-rich flora with nu-merous species yet to be docu-mented. In addition, species ofmosses new to science are also be-ing discovered in the state.

CNPS members have a tradi-tion of adding distribution recordsfor our flora. For the first time, wehave bryophytes listed in the CNPSInventory of Rare and EndangeredPlants of California. Much inventoryand fieldwork remains in Califor-nia. Current bryophyte workers likeColin Dillingham, LawrenceJaneway, Ken Kellman, Eve Laeger,Ronald Robertson, and DavidToren are adding new species tothe state and filling in the distribu-tion range for many species. Thereare also opportunities for plant en-thusiasts to learn more from eitherattending a Jepson HerbariumWorkshop course on bryophytes or

the SO BE FREE bryology for-ays held annually during springbreak (see Workshops on page40). SO BE FREE is an ongoingseries of West Coast forays orga-nized by Brent Mishler at the Uni-versity of California, Berkeley. Formore details and a review of thepast eight forays, visit the web athttp://ucjeps.herb.berkeley.edu/bryolab/trips/sobefree.html.

It is hoped that many moreCNPS members will find the worldof bryophytes rewarding and stimu-lating. There is a whole new worldof plant diversity just waiting foryou to explore!

REFERENCES ANDREFERENCES ANDREFERENCES ANDREFERENCES ANDREFERENCES ANDFURTHER READINGFURTHER READINGFURTHER READINGFURTHER READINGFURTHER READING

Crum, H. 2001. Structural diversity ofbryophytes. University of MichiganHerbarium. Ann Arbor, MI.

Flowers, S. 1973. Mosses: Utah and theWest. Brigham Young University.Provo, UT.

Kimmerer, R.W. 2003. Gathering moss,a natural and cultural history of themosses.Oregon State UniversityPress. Corvallis, OR.

Lawton, E. 1971. (Reprint paperback).Moss flora of the Pacific Northwest.Hattori Botanical Laboratory.Nichinan, Miyazaki, Japan.

Malcolm, B., and N. Malcolm. 2000.Mosses and other bryophytes: An illus-trated glossary. Micro-Optics Press.New Zealand.

Schofield, W.B. 1985. (Reprint 2001).Introduction to bryology. BlackburnPress. Caldwell, NJ.

_____. 2002. Field guide to liverwortgenera of Pacific North America. Glo-bal Forest Society & University ofWashington Press. Seattle, WA.

Shaw, J.A., and B. Goffinet. 2000.Bryophyte biology. Cambridge Uni-versity Press. New York, NY.

Shevock, J.R. 1998. Bryophytes: Littleforests among the trees. Fremontia26(2):38.

James R. Shevock, National Park Service,Cooperative Ecosystem Studies Unit, 337Mulford Hall, UC, Berkeley, CA [email protected]

New species for California are beingdiscovered all the time. Pictured here isJim Shevock documenting the firstCalifornia occurrence of Helodoium blan-dowii from Kings Canyon National Park.Photograph by S. Haultain. Helodiumblandowii is a large pleurocarpous mossrestricted in California to fen habitats.Photograph by J. Shevock.


THE ROLE OF THE AMATEUR IN BRYOLOGY:TALES OF AN AMATEUR BRYOLOGIST

by Kenneth Kellman

am an amateur botanist. Likemost members of the CaliforniaNative Plant Society (CNPS), I

enjoy hiking in a local meadow oralong a creek, identifying the flow-ers and shrubs that I find along theway.

Each spring I run across old bo-tanical friends, struggle to remem-ber the names of the less commonplants, and regularly find plants thatI have never seen before. My pro-cess for identification involves keysand drawings in several references.Often enough, I have to call mymentor and describe the plant tohim. Usually he makes a sugges-tion, or asks a question that pointsme in the right direction, and I con-tinue my search. After I feel com-fortable with an identification of aplant, I make a note in my localflora, or in my Jepson Manual, orperhaps add the name to a list I am

working on. I have been going onlike this for perhaps 25 years, and Ihave never thought that I wouldfind anything that someone else didnot know about . . . until I startedstudying bryophytes.

By trade I am a commercial airconditioning mechanic, and my for-mal training in botany has beenminimal, consisting of one class inplant systematics and one in den-drology at the University of NewHampshire in the early 1970s. I haveno degrees nor have I ever beenclose to getting one. The rest of myknowledge has come from a persis-tent curiosity, and the good will ofmore knowledgeable friends.

Sometime in 1992, I took on aproject to compile a list of the plantsin a local county park where I was adocent. It was a small park of 300acres in Santa Cruz County, filledwith microhabitats, and my list grew

to over 400 species. In an effort tomake the list as complete as pos-sible, I tried to reach every cornerof the park. During one of thosehikes, I came upon a colony of leath-ery looking plants growing in themiddle of a sandy creek bottom. It

Marchantia polymorpha is a common thallose liverwort of springs, seeps, creekbanks, and other wet areas. Pictured here withumbrella-like male branches bearing sperm-producing organs.

Kindbergia oregana, one our mostcommon feather mosses. It is especiallyprevalent on moist logs and soil banks onforest edges. Photograph by J. Shevock.

I


had spectacular little umbrellasspringing up from the thallus, andlittle fringed cups, filled with eggs.

I had a vague memory from mysystematics class that this was a liv-erwort, but I had no idea what spe-cies it was. I went home and startedlooking in my books, but none ofmy references even mentioned liv-erworts. I called my mentor, andasked him, but this time he wasonly able to give me someonesname to call. Eventually I was re-ferred to Bill Doyle at the Univer-sity of California, Santa Cruz. I wasdelighted when he offered to meetme at the park and look at theseliverworts.

I thought I would only showhim this one colony, but inside oftwo hours, he had not only identi-fied my plant (Marchantia poly-morpha L.), but had also shown meten other species of liverworts andhornworts! I had never heard ofleafy liverworts, and had no ideathat they were abundant on the barkof local rocks and trees. I thought Ihad been looking very closely atthis park, yet I had been missing anentire suite of species and their habi-tat. That was the day I was bitten bythe bryology bug. It was a dreamcome true for any naturalist . . . awhole new world to explore.

Bill very graciously taught mehow to collect and then helped meidentify my collections. He gave mekeys, and allowed me to copy de-scriptions from antique books thathe owned. He has continued to helpme to this day.

Soon I bought my own micro-scopes. While my work with vascu-lar plants continued, I was now rec-ognizing the more common speciesof liverworts and hornworts on myhikes. After working on these plantsfor about nine months, I enrolledin the Jepson Herbarium weekendworkshop on bryophytes. Two veryimportant things happened as a re-sult of that seminar. First, I wasintroduced to the study of mosses.Until that time I had purposely ig-nored mosses while I concentratedon the liverworts. Second, I metDan Norris, who was teaching thebryophyte workshop.

Dan provided us with glossa-ries, keys, and bibliographies to getus started, and he encouraged us tocollect. I was off and running. Threemonths later, I brought him a boxof perhaps 150 packets of mosses.He patiently went through themand gave me tentative identifica-tions. But in that box was one mossthat had never before been collectedsouth of Humboldt County. It wason that day I realized that an ama-teur bryologist could make a con-tribution to science.

I knew that I did not possesssome special attraction to raremosses; I was just collecting every-thing that I found. I also learnedthat day that the distribution ofmosses was poorly understood inthis most populous state in the na-tion, and that I could help correctthat.

So I continued collecting andidentifying my collections, but DanNorris had moved to WashingtonState and I lost his expert assis-tance. As a neophyte, I did not feelconfident in my keying decisions,and without Dans confirmationsand corrections I floundered for awhile. Then in the spring of 1998,Jim Shevock wrote an article onbryophytes (Fremontia Volume26(2):1-8). I contacted him andwithin six months or so, my re-search rose to a new level.

Jim wanted to cite my collec-tions in a paper he was writing withDan on the distribution of Califor-nia mosses. I had been working ona list of Santa Cruz County bryo-phytes, but never thought it wouldgo beyond that. Jim encouraged meto start housing my collections inan herbarium, and told me that mywork was significant enough to pub-lish in a scientific journal. TakingJims suggestions to heart, I de-cided to write a Catalog of theMosses of Santa Cruz County, andto submit it for publication.

Eventually, Dan returned fromWashington, and he, Jim, and I metevery couple of months to reviewmy collections and work. I combedthrough the collections in the threeBay Area herbaria, noting all of thecollections from Santa CruzCounty. This review of existing col-lections pointed out exactly howlittle was known about bryophytedistribution here.

Of the approximately 190 spe-cies of mosses that I have docu-mented in Santa Cruz County, wellover half had never been collectedfrom the county before. Fifteen ofthose have never even been col-

Overall aspect of Leucolepis acanthoneura(top), a moss found along moist stream-sides and shaded forest areas. Individualplant of Leucolepis acanthoneura (bottom)showing palm-tree-like growth form.The bracts on the stem are white; leuco-lepis means white scale. Photographsby J. Game.


lected from the central coast of Cali-fornia. Seven of those 15 are stillundescribed species, and local col-lections like mine add to the knowl-edge of range and morphologicalvariation for each one. I still col-lect, and even after eight years, Iam still finding new taxa to add tomy list. My moss catalog has beenpublished in Madroo (Volume50:2), the journal of the CaliforniaBotanical Society, and I am startinga formal catalog of the liverwortsand hornworts of Santa CruzCounty as well as starting collec-tions in Monterey County for abryophyte catalog there.

Collecting bryophytes is like agrand treasure hunt, and it is a greatexcuse to get outside and enjoy na-ture. Publishing a local catalogforced me to collect throughout thecounty, and so I have been to beau-tiful creeks and forests that I hadnever visited before. Another plus isthat bryophytes (mosses in particu-lar) grow everywhereon dry rocks,in the water, on soil, on cement,even in the cityand they can becollected any time of the year.

They are very easy to collectand store. No pressing or mount-ing is allowed, much less required.Just put the plant into a packet,note the collection data, let it dry,and voila! This is nothing like theamount of work required for col-lecting a vascular plant. The pack-ets are small enough that I can keepa hundred specimens in a bureaudrawer. Since these plants desiccatein nature, a dry moss in a packetlooks exactly like a dry moss on arock, and because mosses preserve

Isothecium stoloniferum (top) is a commonepiphytic moss in the temperate rain-forests in northwest California. Anti-trichia californica (middle), a widespreadspecies. Note the closely associated,concave leaves which give a wormlike(julaceous) appearance to the leafy plant. Pseudobraunia californica (bottom),another julaceous moss. Pseudobrauniaforms large bronze-hued mats on rocks.Photograph by J. Shevock.


Studying bryophytes is not onlyexciting for the amateur, it is im-portant. Most academicians haveabandoned bryophyte floristics be-cause it does not attract funding.Because of the discontinuous na-ture of bryophyte distribution (seeJim Shevocks article on page 12),bryologists arent even sure whatplants are rare in our state. It isdifficult to accept that a group ofplants this large can be so poorly

Dicranum howelli (top) is widespread innorthwestern California, and is primarilyfound on forest litter. Atrichum selwynii(bottom), common on mineral soils, is anacrocarpous moss readily recognized byits undulate leaves with prominent costa.Photograph by J. Shevock.

Plagiomnium insigne has some of the largest leaves of any Californian moss. It is foundon shaded and moist soil and humus along springs, streams, and waterlogged areas.

so beautifully, identification can bedone the minute you get in fromthe field, or if that is inconvenient,in 25 years. All that is required isrehydration from a drop of warmwater.

understood in the most populousstate in the US, but it is true, and itwill be true for some time to come.This provides the amateur natural-ist with an opportunity to make asignificant contribution to the ex-isting body of botanical knowledge.

There are many opportunitiesfor amateur bryologists to make adifference in our understanding ofthese plants. There is, of course, afloristic project like mine, which


involves making a list of bryophytesin a park or even an entire county.Most of the counties in Californiarepresent giant holes in our knowl-edge, waiting for someone to makeconcentrated collections. Othercounty studies have revealed spe-cies new to California, and evenspecies new to North America.Without extensive collection it isimpossible to know what is rare andwhat is common. Creating a localcatalog is an excellent way to learnbryophyte identification. If a cata-log seems too ambitious a project,just making collections is a valuablecontribution. Local herbaria are al-ways hungry for properly identi-fied, well-labeled specimens.

For those with a camera and aclose-up lens, there is always a needfor quality photodocumentation.Photographing bryophytes is noto-riously difficult, and will becomevaluable as interest grows and fieldguides come into demand. Likewise,technical artists could draw bryo-phytes for articles describing newspecies, or for a small local flora.

Cataloging herbarium collec-tions is an invaluable service thatcan be provided especially by thosewho enjoy working with comput-ers. Very few herbaria in our nationare yet part of computer databases,so volunteers can make a huge dif-ference here by entering data intocomputers. Once collections arepart of computer databases, thiswealth of information suddenly be-comes accessible to people through-out the world via the Internet. Abryologist studying a particulartaxon could then query a databaseand request loans from the her-barium, saving countless hourspouring over specimens.

Public education also offers theamateur additional opportunities toadvance the field. Slide shows andhikes that focus on bryophytes are agreat way of introducing people tothese wonderful plants. Even if yourknowledge is limited to recogniz-ing the major bryological groups

and some of the basic bryophytebiology, people still love to see thesetiny plants on a wildflower hike.

How do you get started? I heart-ily endorse attending the annualbryophyte weekend workshopsponsored by the Jepson Her-barium. This hands-on class pro-vides a great foundation for yourstudies, and includes collection anddissection techniques, recognitionof the various bryophyte groups,practice using keys, and an over-view of bryophyte biology. (Thenext Jepson bryophyte workshopis February 21-22, 2004. For de-tails see http://ucjeps.berkeley.edu/jepwkshp.html, or write to the JepsonHerbarium, University of Califor-nia, 1001 Valley Life SciencesBuilding, #2465, Berkeley, CA,94720-2465.)

Another source of good infor-mation and contacts is the bryo-phyte listserve on the Internet. Tojoin, send an e-mail, with the singleword subscribe in the body ofthe message to [email protected] annual bryophyte foray SOBE FREE sponsored by BrentMishlers laboratory at UC Berke-ley is a great event for amateurs tomeet other bryologists of all skilllevels. Information on the event isposted at http://ucjeps.berkeley.edu/bryolab/trips/sobefree.html.

As your interest and commit-ment grows, you will need accessto microscopes and a good refer-ence library. Used microscopes canbe obtained from local microscopetechnicians for a reasonable price,and investing in a personal libraryis well worth the expense. Cur-rently, there is no Jepson Manualfor California bryophytes, so anumber of floras from NorthAmerica and beyond must be usedfor identification. I am the first toadmit that this work involves a longlearning curve, so finding yourselfa mentor is almost imperative. Butthe bryologists I have met haveproven to be a friendly and gener-ous lot, and will be more than happy

Top photograph: Dan Norris (left) andJim Shevock (right) during a Jepsonworkshop in the Sierra National Forest,near Minarets pack station. Photographby S. Markos, courtesy of the JepsonHerbarium, UC Berkeley. Bottomphotograph: Dan Norris (left) and JimShevock (right) working in the UniversityHerbarium bryophyte collection, UCBerkeley. Photograph by B. Ertter.

to help you if they sense a commit-ment to learn.

I encourage you to polish yourhand lens, and then open your eyesto the tiny world that you have beenwalking by every day of your life.

Kenneth Kellman, 9870 Brookside Ave., BenLomond, CA 95005. [email protected]


MOSSES IN THE DESERT?by Lloyd R. Stark

hen I first came to theMojave Desert as a stu-dent intern in botany, it

was so hot and dry that I was amazedthat plants, least of all mosses, couldsurvive the heat and scarcity of rain-fall. After all, mosses require a moistenvironment to grow and repro-duce, and the Mojave Desert is thehottest and driest region on the con-tinent. Nevertheless, my instructorin botany at Humboldt State Uni-versity, Daniel Norris, had con-vinced me that mosses did indeedinhabit the desert, and he had

briefed me on what to look for basedupon the northeastern Californiahigh desert region.

Many years passed before I tookup a permanent residence in theMojave, and at this point I had dis-tanced myself from a study ofmosses. Although I had spent sometime in the Chihuahuan Desert ofsouthern New Mexico, when I cameout to the Mojave Desert of south-ern Nevada and California, I hon-estly did not expect to encountermuch in the way of mosses in thelower elevation desert terrain. I re-

call very distinctly when the pas-sion to study mosses returned. Ashort trip into a desert canyon nearLake Mead allowed me to surveythe area for mosses, fully expectingto find very little in the way of theseplants. After all, generations ofbryologists had routinely avoidedthe desert with the preconceivednotion that it represented a vast voidharboring few if any species able totolerate the heat, lack of water, wind,and general severity of weather.

Botanical collectors of flower-ing plants in the desert often re-strict themselves to a few weeks ofcollecting in order to avoid the heat.After spending nearly 15 years inthe eastern temperate forests wheremosses and liverworts are abundant,and then relocating near Las Ve-gas, I can comment on this prevail-ing viewpoint of mosses being gen-erally absent in deserts: it is utterlyfalse. To my surprise, this short hikerevealed several species of mosses,at which point my interest in theselittle plants was rekindled. So struckwas I with this discovery that mycareer path actually changed at thatmoment, and I was drawn back intothe field of bryology. This was aboutnine years ago, and I have neverlooked back. The mosses of theMojave Desert have offered an out-door laboratory heretofore un-tapped, and have yielded some ofthe most fascinating patterns of re-production and survival amongplants.

Now, strictly from the stand-point of diversity (the number ofspecies in a given area), it is truethat there are fewer species in theMojave Desert than surroundingareas; Jim Shevock is estimatingabout 125 species as of this writing.While this number represents asmall proportion of the estimated600 species of mosses in California,

Typical Mojave Desert habitat for Crossidium species. A wash runs through the centerof the photograph (covered with green vegetation), and Crossidium is found at the baseof the small rocks on the north-facing side of this wash. Photograph by L. Stark.

W


the desert species are perhaps moreinteresting because: 1) several glo-bally rare endemics occur in deserts,even a new liverwort awaiting de-scription that will be named afterthe Mojave Desert; and 2) the spe-cies inhabiting the desert exhibitsome amazing survival strategies ofdesiccation tolerance and reproduc-tion found nowhere else in theworld.

Although qualifying definitionsof deserts vary widely in the litera-ture, the boundary between desertand semidesert can be recognizedas occurring below the 120150 mmisohyet of annual precipitation. Bythis definition, only the westernedge of North Americas desertsconforms to a true desert, namelythe Mojave and western Sonorandeserts (inclusive of the ColoradoDesert of Southern California).Compared to other deserts of theworld, North American deserts arenot only small in area, but youthfulin age. As judged by paleobotanicalevidence using packrat middens,present floristic compositions ex-tend only to circa 8,000 years ago.The boundary of the Mojave Desertcan generally be said to follow thedistribution of creosote bush (Larreatridentata) and also the Joshua tree(Yucca brevifolia).

THE WAITING GAMETHE WAITING GAMETHE WAITING GAMETHE WAITING GAMETHE WAITING GAME

How are these rootless plantsthat have no water storage capacityable to survive the rigors of thedesert, where rainfall is not only onthe order of millimeters per year,but is more sporadic and unpre-dictable than any region on earth?Mosses have no roots, no water stor-age organs, few protective pigmentsto diffuse the suns rays, and occupyonly the surface of the substrate onwhich they grow. Therefore, theydry out as rapidly as the soil driesout, which can range from a fewdays following a winter rain, to afew hours following a summer rain.In the Mojave, most of the rainfallis during the cooler winter months,so herein lies a major irony insofaras desert mosses are concerned: theyare shade-adapted plants that dobest when temperatures are cool andmoisture is readily available.

Optimal growth conditions fordesert mosses surprised everyone.They prefer it to be 6070F un-der very dim light (full shade). Istruggled for years trying to growdesert mosses in a growth chamberuntil an undergraduate student dis-covered the plants have to beshielded even from the direct lightof a grow light! From April throughNovember, mosses in the desert tol-erate the heat and desiccation in adormant state. During this periodof blistering heat, the cells do notdie, but remain physiologically aliveyet totally inert (respiration is un-detectable!).

Going nine months withoutwater is a trick that not even themost heat tolerant Mojave Desertflowering plant can carry out. How-ever, this feat is relatively easy for adesert moss, most species of whichare able to tolerate several years oftotal desiccation and then spring tolife when wetted. After eight yearsin dry storage in the dark (in anherbarium), one specimen, to ouramazement, showed 100% viabilityamong its stems, and we still do not

know just how long a desert mosscan survive in a dried state. Desertmosses are photosynthetic oppor-tunists: they capitalize on the win-dow of opportunity, from aboutDecember to March, when a suffi-ciently hydrating winter rain oc-curs. Within hours of a rain theyare carrying out positive net photo-synthetic gainmaking sugars.

Thus the life of a desert moss isreally a waiting game, where theplants patiently await a winter stormthat may only occur every few years.Recently I followed a few popula-tions of the most desiccation-toler-ant moss in the Mojave Desert, aspecies in the genus Crossidium, fora period of one year in order todetermine the duration of the hy-drated versus the dormant dry state.

The desert biological crust of the MojaveDesert. Black patches on the soil surfaceare composed of mosses and lichens, withthe dominant moss Syntrichia caninervis.Photograph by L. Stark.

Four desiccated plants of Pseudocrossidiumcrinitum (top) from the Mojave Desert.Leaves of desert mosses often show a char-acteristic spiral twisting of the leaves aboutthe stem. A wetted patch of Pseudo-crossidium crinitum (bottom) from theMojave Desert. This hydrated conditionis evident only a few days following a rain-storm. Photographs by L. Stark.


During this year (2001), the areaaround Las Vegas received slightlymore (120 mm) than its normal an-nual rainfall (104 mm). These plantswere fully hydrated for a total of 31days in 2001, partially hydrated (inthe process of drying down) for atotal of 35 days, and entirely desic-cated for the remaining 299 days.During one stretch these plants tol-erated 147 consecutive days of des-iccation. Fully wetting these plantsrequired about 4 mm of precipita-tion, as rain.

The mosses, then, wait for agood winter rain, after which, dueto the lower temperatures of winter,they can remain hydrated for severaldays. The first day of hydration isspent repairing their tissues from thedamage of the wet/drying cycle ofevents (primarily membrane dam-age). From the second day onward,they can grow and reproduce. It is intheir patterns of reproduction thatmany an interesting tale can be told.If a summer thunderstorm hits, it isvery bad news to the mosses. Tem-

habitats. About 80% of moss spe-cies are bisexual in true desert habi-tat, compared to an expectation of4050% of mosses at large. Bisexu-ality allows the male and femalereproductive structures to be inclose proximity, allowing self-fer-tilization to occur, and thus theplants reproduce sexually by pro-ducing large quantities of airbornespores.

In mossesas described byDaniel Norris in his artic

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