Selbyana 26(1,2): 155-158.2005. How MANY ORCHID SPECIES? ROBERT L. DRESSLER Missouri Botanical Garden; Florida Museum of Natural History; Marie Selby Botanical Gardens; Mailing address: 21305 NW 86th Ave., Micanopy, FL 32667, USA. Email: [email protected] ABSTRACT. In the 1980s, careful estimates of the size of the Orchidaceae clustered around 19,000. A new provisional checklist suggests 24,500 species of orchids, approaching the "improbable maximum of 25,000," as seen by John Atwood. Recent lists from Mesoamerica agree closely with the 20% increase indicated by the provisional list. Will the next two decades bring in another 5000 new orchid species? The answer is unknown, but there are clearly many new species to be found in tropical America. Showy, new, large-flowered species are relatively few, rather the vast majority of species are small-flowered, if not microscopic. Ephemeral flowers, such as Sobralia, Palmorchis, aud the Triphoreae, have special problems associated with their identification, for which most field-collected herbarium specimens are nearly useless. In practice, most large-ftowered orchids are poorly represented by herbarium specimens, and even many small-flowered species are scarce in the herbaria. Only abundant and widespread species, such as Epiden­ drum radicans or Habenaria monorrhiza, are really well represented in the herbaria. In Central America, it is interesting to compare Costa Rica, with its tradition of resident naturalists, with Panama, where resident naturalists have been very few. Now the Panamanian orchid flora is rapidly catching up with Costa Rica, but both countries have significant areas that are poorly sampled. Much work remains to be completed, but when someone looks for them, many more new species will appear. Key words: Alpha taxonomy. systematics. plant collections INTRODUCTION Even here, in the United States, we do not know enough about what grows where. How much I'm told that Linnaeus, in his later years, ex­ worse must the problem be in tropical areas? pected a few hundred new plant species to be In the 1980s, several attempts were made to found in Africa and other remote areas. He re­ calculate the size of the Orchidaceae (Atwood ally thought that we had named most of the 1986), with the totals clustering around 19,000 world's flora. Since then, many others have species. New species continue to appear, and thought that we really knew most of the world's careful study often revives supposed synonyms. flora, but new species continue to appear nearly A recent tentative checklist (Govaerts et al. everywhere. We need to know as much as we 2003) indicates 24,500 as the probable number can about the world's flora and fauna, both for of orchid species currently known. This number practical purposes and for more intellectual mo­ approaches the "improbable maximum of tives. Current attitudes favor molecular system­ 25,000 species" as seen by Atwood (1986). atics, which undoubtedly has a great deal to of­ Thus the numbers have increased by more than fer, over "old-fashioned taxonomy" (Wheeler et 20% in the last 20 years. Checking the still in­ al. 2004). Much of the real pressure against complete manuscript of the Orchidaceae for the "old-fashioned taxonomy" comes from univer­ Flora Mesoamericana and recent checklists for sity administrators, who lust after overhead from Costa Rica and Panama (Pupulin 2002a, Correa large grants. Old-fashioned taxonomy may need in press), again indicates an increase of ca. 20% a bit of travel money from time to time, but it since 1979. I do not expect new species to stop is quite inexpensive as compared to molecular appearing this year, or even this decade. work. Molecular analysis has greatly improved It is interesting to contrast our growing classification above the species level, but it has knowledge of the orchid floras of Costa Rica and limited use at the species level. To be honest, Panama, neighboring countries with relatively most molecular work would be quite meaning­ friendly botanical competition. Costa Rica had less without "old-fashioned" identification and many resident naturalists and botanists in the documentation of the samples analyzed. early 1900s. This is reflected by the frequent use A recent issue of Systematic Botany has a pa­ of the epithets: a(faroi, acostae, biolleyi, bradei, per and a commentary on the decline of local or bradeorum, brenesii, jimenezii, lankesteri, plant collection in the United States and the pittieri, sanchoi, tonduzii, valerioi, and wercklei, problems this causes in studying speciation, ex­ all honoring naturalists who sent material to Eu­ tinction, changes in distribution, and invasion by rope or the United States. In Panama, C.W. Pow­ exotic species (Prather et al. 2004a, 2004b). ell was virtually the only resident who regularly 155 156 SELBYANA Volume 26(1,2) 2005 1500 1372 1400 1300 1200 1100 1000 ~~-=~ --- --- --- --- --- --- --- --- --- --- --- 900 800 700 600 500 400 300 200 100 1920 1930 1940 1950 1960 1970 1980 1990 2000 FIGURE 1. The numbers of orchid species recorded for Costa Rica (0) and Panama (lIl!) in floras and check­ lists, beginning with the checklist by Schlechter (1918) through current lists as of early 2004, with some known but yet unnamed species in the final count for each country. prepared specimens for study. Logically, Pana­ be better sampled than tiny plants with nearly ma, with the greater area and high mountains at microscopic flowers, but the pattern is more each end, should have the richer orchid flora, complex than that. Very small flowers are, cer­ and FIGURE 1 suggests that Panama is rapidly tainly, poorly represented in herbaria. A good catching up with Costa Rica, although much of example is the genus Stellilabium. The flowers Darien is still quite hazardous for plant collec­ are very small or tiny, and in Central America tors. the plants are usually quite leafless at flowering, My contention that orchid floras are poorly with a flattened rachis as the primary photosyn­ sampled is supported by the rather frequent find­ thetic organ. In 1969, I saw a small flowering ing of the same inconspicuous, unnamed species tree in central Panama and pulled down a branch almost simultaneously in two or more widely to press material of the tree. Once it was in hand, distant places. When I was first sampling the I noticed funny little string-like things on the cloud forest orchids of Cerro Jefe in Panama, twigs, some of them with tiny purple flowers. several tiny orchids that T found were soon iden­ Thus, J collected an unusually complete collec­ tified as species that Hawkes and Heller had just tion, which became the type specimens of Stel­ described from Nicaragua. Some of these spe­ lilabium aciculare in 1999. This species seems cies have not been found in Costa Rica, but I'm to be one of the commonest speci.es in Costa sure they are there. Similarly, Franco Pupulin Rica and Panama. At that time, I published three recently described Ornithocephalus monteale­ other species, and Franco Pupulin continues to greae from Costa Rica (Pupulin 2002), while find new species. Now that he has the "search Cal Dodson was preparing to describe the same image," one of his recent emails said that it was species from Ecuador. "raining stellilabiums." One would expect large and showy orchids to Botanical collectors can scarcely overlook SECOND IOCC PROCEEDINGS 157 plants with larger and more colorful flowers, but working on orchid classification is in the area, really showy species are poorly represented in they are almost always delighted to help. Cer­ museum collections. In remote wilderness areas, tainly we need to educate them about the im­ at least, one would expect large-flowered species portance of locality data and to emphasize the to be collected more often then less conspicuous botanical interest even of ugly little flowers. ones. I think, in fact, that in settled areas, local There is no doubt that the authors of the Con­ residents remove most of the large-flowered vention on International Trade in Endangered plants not hidden in the treetops, before any bot­ Species of Wild Fauna and Flora (CITES) had anist gets there. Michael Grayum (pers. comm.) good intentions, but it is equally true that good complained that when a Costa Rican plant col­ intentions may not be enough. In the last orchid lector working for INBio finds the national flow­ conservation symposium held at Selby Gardens er, Guaria morada (GuarianthelCattleya skin­ (1997), a representative of CITES explained that neri), in flower, he takes the plant home to moth­ orchid growers wishing to exhibit their plants on er, wife, or girlfriend, rather than pressing a the other side of an international boundary, but specimen. Mike said that if he ever found such unable to take the plants across legally, could a plant in bloom, he would mash (press) as many legally take cut flowers to the exposition. Jim specimens as possible. Of course, it is usually Ackerman then asked, "You mean that they can relatively easy to cut off an inflorescence, an import flowers legally, but if we press one of older pseudobulb, and a couple of older leaves, those flowers to make a permanent record, it be­ to make a good specimen without harming the comes illegal contraband." "Well, yes, as the plant, either in the field or in the garden. How­ law now stands, that's true," was the response. ever, I don't recommend this for Stellilabium. I strongly feel that pressed specimens, flowers A special problem occurs in those orchids in alcohol, and tissues in silica gel are not "com­ with ephellleral flowers, such as Sobralia, Ep­ merce," in any sense of the term, and should istephium, or Triphora.