PLANT TAXONOMY IN THE HAWAIIAN ISLANDS The Hawaiian flora contains many taxonomically corn l a and poorly understoodgroups that require further study in the Jield!

David H. Lorence, Warren L. Wagner , and Derra l R. He rbs t

Taxonomy, or systematics, is an attempt to catalog and study elements of the living world, both present and past, and to understand the rocesses that have led to the remarkable diversity of living organisms. At Yeast million kinds of livine t h in s have been described and share our biosubere. - - Plant taxonm:y (sybtcni;r~ic botany) convey our best understandin; If pat- tzrrs of n:ltural biological diversity in plant,. Sincc txwnomy is ;, very funct~onal science. i t must he tlcuble e n o ~ g h to reflect changes as we ohtnin new iniormation thst helps us hetter understand the organim, we are st.dy- ing and the relationshipr among them.

It is usef~il to review th t i evolution of ~ l a n t tasonomv. which has resulted in our modern svstems of classification. &lore than 2.000 vears aeo the Greek pli~losophcr ~h&~hr ; i s tus , a pupil of Aristotle, recognixd thedi?ferenc& between trees, shruna, and annual, biennial, and perennial herlis. Know11 the "father of hot;~nv. Themhrastuh ;dw u n d e r ~ t ~ ~ o J the sccd. stem. and leaf d~ficrcnces hctnccti monochyledons m d dlcotyleduns as well as mnnv other mf~rphologiral d~fference\ In veqctative and 11 %dl feature,, many of these formed the basis for later systems of classification.

The practice of referring to organisms by descriptive Latin phrase names known as polynomials (many names) began in medieval times. The concept of genus, a group of closely related species to which an orgalusm belongs, dates back to the end of the 17th century, when itwas used i? herbals, high1 illustrated works about plants considered to have medlclnal value.

?he system of naming living things was simplified considerably in 1753 when Carolus Linnaeus published his Specie~Plantayn $Species of Plants), a landmark work that contained br~ef analyt!cal descnpttons of every known species of plant as well as references to earller works. For convenience, Limaeus introduced a binomial (two-name) system prig both a generic and a specific name for each plant. In addition to provldlng the first consistent use of the binomial system, Linnaeus instituted two systems of plant classi- fication, an artificial classification system for the rapid cataloging and identifying of plants based primarily on the number of floral parts, and the basis for a natural classification system, that is, one reflecting the actual evolutionarv relationshios of ~ l a n t s to each other.

Du&itlic 18th and l~thcenturies a number of cl~ssification ?,terns, primar~lv descripti\e in scope, were developed. The publication of Darwin's Origin q'Species in Id59 had a great impaci on plant systematic?, and the

concept of evolution began to be reflected in classification systems of the For the first time it was recognized that species and higher :,";: rGk"Zrived from progenitors (ancestral forms) through evolution

b natural selection. The concept of phylogeny, or evolutionary relation- s&os of oreanisms to each other, was thus formed. It was to be a most i m ~ o r - rani charaseristic of all later .y.tems of cl;irsii~c~tim. \Ian! ollicr \ . lcnk were subsequently developed to reconcile the nlorph8~logiz41 frxlurch ~ l a n t s with an evolutionafy interpretation of these-features.

Although in the past much systerrtat~c rescxch \ r ; l I I A ~ ;~lrnost ml~rcl!. upon "class~cal" morphological and anatomic:ll siniil~ritiz\ and di l<zrc~i~~. . , modern biosvstematics (biological systema~ic\) nrnv 1 1 : ~ ~ at its di\r]<lr:~I ;I whole soectium of new tools and technioues for ohvlozenetic intkrnretation

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and so lhon of taxonomic problems. nibchemich bnGironi quantiii;atwn oi DNA (genome analysis) and studies of i~rotein molecules can he med I,] undersiand relationshbs of soecies to one another. Chemical taxonomv (chemotawonomy) prohdcs ahlitional data for thc systematist :mJ is u;cful :n determming the parental spccics in cases of suspertcd hybridiwtion. Uoth sc~nning and transmission electron microscopy (SliM and TI31) are powerful tools now widely used in systematic studies, for examplc, examination oi trichomes (hairs), pollen, and sieve tuhe plastids (storage orgmelles or little orcans found in vascular olant tissucl. In addition. chromosome number and behavior, karyo& analysis, hybridization, &ogenetics, and breeding systems are aspects of biosystematic studies that provide important data for understanding plants taxonomically and pbylogenetically. Inter- disciplinary collaboration between biologists is alw becoming increasingly important.

The most modern and widely accepted systems of plant classification today are essentially based on a synthesis of all available data.

A HISTORY OF BOTANY IN THE HAWAIIAN ISLANDS

Ear ly Explorers Because of their isolation. the Hawaiian Islands harhor a unioue and ~ ~-~~

~ ~ - - x ~ ~ - -~ ~

astonishing flora with a highe; degree of endemism than any comparable area of the world. About 91% of Hawai'i's flowering olants are endemic (found nowhere else) (Carlauist 1980: Sohmer and C%stafson 1987: see also ~ ~ ~~ . - ~ - ~-

kanr.>hiro, this vcdunle). TI& iir,t \\'&tern botanist to explore and collect specimen, in [he 11aus11m Archipr1:ieo ua\ David Selwn in 1779, on Captain Jimes Cook's third vovaee. an; othkrs followed. most notablv Archihdd - ~~~~. ~ ~

\lenzie.;, Adelbert ('han%io, Charles (;audichaud-neaupr6, a i d James Mac- r x . Finallv, a team of sclenti,~. \uth the U.S. t.xploring Expedition com- manded b<Charles Wilkes in 1840-1841 ment skmonths in the Hawaiian

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Islanas miking exten$ive natur3l histury chlections that resulted in the published de\criptiunh 111' nl:in\ new species. During the same period, the lslmds were also ri,ited h\ a number o i inde~endent travelers and natural- ists, some of whom collec<ed plants (Kay 1972).

Earlv Resident Botanis ts 'l'he great exploring expeditions finally came to an end in the late 19th

century. 1)escend;mt.; of the earlv misslonary familes subsequently became

Planr Tmmrmr?y\Lorcrlce ef al. 45

interested in natural history and made biological collections which they sent to scientists in America or Europe.

An im ortant phase began when botanists such as Hillebrand, Mann, Brigham, Jock, and Forbes went to the Hawaiian Islands and made significant collections while residing there. William Hillebrand, a German physician and accomplished botanist, lwed in Honolulu for 20 years and was one of Hawai'i's most renowned doctors. During his stay in Hawai'i (1851-1871), Hillebrand explored all the larger Islands and collected numerous herbarium specimens, sets of which were deposited in the B.P. Bishop Museum in Honolulu, Mel- bourne, Berlin, and Zurich herbaria. His extensive living collections now form part of Honolulu's Foster Botanic Garden. Charles Forbes, the first full-time botanist at the B.P. Bishop Museum, was appointed in 1908. His many herbarium specimens became the nucleus of the rich Hawaiian collec- tions housed there todav. Josevh F. Rock, who came to Hawai'i in 1907 from Austria, spent about 12years siud\in$ the flma o i Ilunaii and cnllected numerous herbarium specimens. . . \ n lm~ thc other early resident naturalists. Jules Remv, Theo Ballleu, Valdemnr tinudcon, and .John \I. 1.vdyatc all . - desenre mention for their contributions.

Recent Resident Botanis ts l k o great stt!dents of the Hawaiian flora have lived and worked in the

Islands for many years. Otto Degener (recently deceased) came to Hawai'i in 1922 and collected extensively. He distributed a large series of duplicate plant specimens to a number of herbaria world wide. Harold St. John came to teach at the University of Hawaii in 1929 and has pursued his studies of Hawaiian plants since then, making extensive collections.

PUBLICATIONS ON HAWAIIAN BOTANY

Existing publications on the flora of the Hawaiian Islands fall into two main categories: systematic studies, including monographs and revisions, and floristic treatments (floras). An early example of the first category is Rock's monoma~h of the Hawaiian soecies of the tribe Lobelioideae of ~am~anulac~ae'(.'lohelioids"), in 1919. Although many tarmomic studiec on Hawaiian plants exist. a large numher were pubhhed hy hotan~sts such as E.E. Sherff. who worked exclu&elv with driedherbarium boecimens and never visited llaw~i'i. On the other hand, several excellent ex:;rnplcs o i modem biosystematic treatments incorporating field ohscrvation with morphological, anatomical, cytological, and hybridization data cxkt. \lore work of this type is badly needed for many Hawarran group*.

The first comprehensive account of the Ilawaiidn flora 3s a whole is Hillebrand's bloru ofrlrr lluwuiiun Islands (1x88. rc~uhhshed in IOXI). based on extensive iollections and field observationk AIthough now dated, it has been used bv generations of students of the Hawaiian flora. Rock's (1913, reprinted in 1972 jhdigenous Trees of the Hawaii? Islands also falls into the floristic categoly. Degener's Flom Hawaiiensu, begun in 1932, is an ongoing series comprising some seven volume^ conslst!ng of treatments with taxonomic keys, descriptions, synonymy, and h e drawngs (see Mill ef al. 1985 for details). Although quite useful it is unfortunate!y not complete. A num- ber of popular works on Hawaiian plants also exlst, mcluding Marie Neal's In Gardens of Hawaii (1965) and the recently published Plants and Flowers

ofHawaii (Sohmer and Gustafson 1987). the last replete with excellent color photographs. The forthcomingManua1 of the Flowering Plants of HawaiT, coauthored by W. Wagner, D. Herbst, and S. Sohmer, 1s in press. The Manual will not only offer consistent, synoptic treatments with a biological basis for flowering olant families in Hawai'~ but will also highlight and discuss nroblem& and taonomicallv com~lex eenera a d sogcies erouos. However. ;he rc~rLtrlon of some problems is 6 c y o d the scope h a flo;hr~! trqatment. :is olmts need to be studied througli 3 combination of field t~h..cn.ntlons, biosvstematics, and other moderntechniaues as well as a classical taxonomic nppioach. By callmg attention to these p;ohlems, the authors hope to \liniulate new interest and research hv tithers.

MAJOR PROBLEMS

The Hawaiian flora contains manv taxonomicallv comolex and ooorlv understood groups that require furthe; study in the geld. klthougha laGe number of botanical soecimens have been collected in Hawai'i, there has been relativelvlittle studvof natural oooulations in the field and few attemots ro cokdate field r&ults with &ra'from biosystematic studies. One mirjor ~roh lem is that many previous l a r u n ~ m ~ c studies were based entlrelv on dried herbarium soefiine~s. Therefore. taxonomic entities such as sbecies or varieties were oft& dcscrihed, with no biological understanding of thc plants, on the hmis of one or a few specimens. In realitv, t h ~ specimens m.,! nierelv reoresent stages in a continuous ranee of variation andnot biological enti tie<. Fieid studies are therefore'necessary to understand u lh;r I > rc,prc- r e n t d i n ;I hiological sense. Hahitat disturbances h) feral hn in l ;~ l , . h~ltn;,n nai! it!, ;~nd ~nva\ion by alien \peciesare all becoming incre;,%ingl\ *i,ucr.,. Stu r l~c~ o i pl;tnt ;rnd arlirnal populations in the field and applic:~tion . ~ i nod ern tr~cI111 ,,ucs are cimtrngent on protection olrlletr h:,hi!;~t..

In dJttiori, :1 l n r ~ e influx ofcollections made over the recmt \c:lr, i , vieldine soecimens wiiich are critical to an understanding of oroblim erouos. W!wr cdic.a!ms represent new distributional rccords 6 r islknds ;tr~d&i inrludc 11cu undescr:bed taxa. Since the existing 1:rxonomic and flor~htiz literature is scattered and varies reatly in scope, quality, and consistency, it is obvious that a changing, mo ern flora is required to incorporate and synthesize all the information.

t Another maior oroblem in olant taonomv in Hawai'i todav is that more

trained taxonom'ists'and studenk, hoth at the L.rxltratc and undergraduate levels, are needed. Fund~ng for pc:,t.nni.l. :I\ \\c:I ar for research e uipment, herbarium suoolies. and field u~ork. i \ ;I ni:tr~>r wnmaint. Manv of i e exist- ing facilities &id idrastructures :,r< ~ . w r . l i l ! ;~dqua :e (for exahple, those at the B.P. Bishop Museum :,nd I'.laik 'I'rtq~ir;~l ht;:nical Garden), hul an active research program always requires some expansion.

RECOMMENDATIONS

It is suggested that available time :and resources be focused on field studies and 3n:ilyses of olanls with a~ecific taxonomic oroblems. The result.; will not only contribute-to conservaiion, but also will drovide essential data on the btology, evolution, and relationships of plant taxa. Modern

Plant Taronomy \Loreme el 01.

biosystematic revision5 and mt~nogr:~phs dealin with Hawaiian plants arc few, and further e f fo r t s k h i ~ ~ ~ l d bc ul this type. . 6 ore funding for plant taxonomy, holh rescarcli dnd pcr,onnel, should be sought.

Important References: Herbaria

The herbarium is an extremely important reference for conservationists a well as taxonomists. It is apermanent data base and reposito for voucher specimens of the plants being studied and is important as a rezrence col- lection for determining and verifying plant identity, thus serving as the basis for scientific studies and publications. The herbarium is also an important reference at the State level (for example, the herbaria of the B.P. Bishop Museum, Pacific Tropical Botanical Garden, University of Hawaii, and National Park Service), as the specimens yield information on the plants' distribution ( ast and present), habitat, range, phenology (flowering and fruiting timesy, and morphology.

Important References: Literature

Bamam, E.B. 1933. Ma11ua1 ofHowailan Afosser. Bishop Muscum Bulletin 10. Bishop Museum Prcss, Honolulu.

Barrmm, E.B. 1939. Supplement to manual of Hawaiian moss=. Bernice PatroltiBisltop Museum Occosionol Papers 15:93-108.

Carlquist, S. 1980. Hawaii: A Natrrral Hislor).. Pacilic Tropical Botanical Garden, Lawai, Kauui, Hawaii.

Hillebrand, W.F. 1981. FlomoJlRe Hawoiiorr Is10,lds. Luhrecht and Cramcr, Monticcllo, New York. (Facsimile of the 1888 edition.)

Kancshiro. K.Y. lthis volumel Uniaueness of Hawili'i's hiota. Kay, E.A. 1572. Hawaiiannatural history: 1778-1900. Pp. 608-653 IN E.A. Kay (ad.), A

Natural Hist- ofthe Hawaiian lslorndr Sdecled Readi!rp Univ. Press of Hawaii. Honolulu.

Magnusson, A.H. 19%. A catalogue oI the Hawaiian lichens. Arkiv. for Botanik 3223-W.

Mill, S.W., W.L. Wagner, and D.R. Herbst. 1985. Bibliography of Otto and Isa Degencrs' Hawaiian floras. Taron 34(2):229-259.

Ncal, M. 1965. 1,) GardensofHowaii. Bishop Museum Special Publ. 50. Bishop Museum Press, Honolulu.

Rock, J.F. 1974. 77ze Irzdipr,,mcs Trew of the I f m i i o n Idmds. Pacific Tropical Botanical Garden, Lawai, Kauai, Hawaii, and Charles E. Tuule Co., Rutland, Vermont and Tokyo, Japan. (Reprint of 1913 edition.)

St. John, H. 1973. Li,~t orzd S u n l n l o ~ of the Flowering Plants in the Hawaiian Is(ands. Pacific Tropical Botanical Gardcn Memoir 1. Lawai, Kauai, Hawaii.

Sohmer, S.H., and R. Gustafson. 1987. Pla~zls and Flown ofHawaii. Univ. Hawaii Press, Honolulu.

Wagner, W.L., D.R. Herbst, and S.H. Sohmer. In press. Ma~tsoloftheF1o~rrrir~gPla~zt.r of Hawai'i. Bishop Museum and Univ. Hawaii Presses, Honolulu.