From Plant Press, Vol. 3, No. 2, April 2000.
By Robert DeFilipps
Not unexpectedly, Madagascar, the fourth largest island in the world, is the home of Madagaster, a genus comprising five endemic species of Asteraceae. These unexploited composites represent only a fraction of the endemic plants, many others of which have become cosmopolitan tropical ornamentals, that were discovered in this gigantic island, which is only 50 square miles smaller than the Brazilian state of Minas Gerais. Isolated in the Indian Ocean east of Mozambique, Madagascar’s flora comprises around 6,000 endemic plant species, equivalent to 80 percent of its total flora. There are six endemic families, including the arborescent, characteristically spiny Humbertiaceae (named for J.H. Humbert, 1887-1967) and equally spiny Didiereaceae (named for A. Grandidier, 1836-1921); spineless trees would be pointless in these dry habitats. By way of contrast to the enormous size of Madagascar (Malagasy Republic) at 226, 657 square miles, the neighboring, but less frequently contacted Comoro Islands (Great Comoro, Anjouan, Mayotte, Moheli), occupy exactly the same recorded area as Plymouth County, Iowa or Hyde County, South Dakota (863 square miles).
The botanical gifts once endemic to Madagascar, which now boldly exhibit an “aspect dominance” wherever they have been planted in the tropics and subtropics, or when grown as indoor house plants, are a parade of desirable species including the traveler's tree (Ravenala madagascariensis, Strelitziaceae); the crassulaceous panda plant (Kalanchoe tomentosa) and flaming Katy (K. blossfeldiana); crown-of-thorns (Euphorbia milii); the water-loving umbrella sedge (Cyperus alternifolius); the blue-leaved Chancellor’s palm (Bismarckia nobilis); yellow butterfly palm, the most abundantly cultivated ornamental palm in the world (Dypsis (Chrysalidocarpus) lutescens); the fenestrated Madagascar laceleaf plant, an aquarist’s dream (Aponogeton madagascariensis); the Madagascar periwinkle, highly decorative and containing 60 alkaloids, some valuable for treating forms of cancer such as children's leukemia (Catharanthus roseus, Apocynaceae); the ubiquitous red-flowered “flamboyant” (Delonix regia, Caesalpiniaceae); and the purple-spined, though regrettably non-suckering, Pandanus utilis. Carnivorous plant fanciers seek Nepenthes madagascariensis. Unfortunately, by contrast, scarcely any food plants originated in the region; seemingly as compensation vanilla growing is a major industry in both Madagascar and the Comoro Islands today.
Over the last few centuries, Madagascar’s oddly shaped plants with bulging trunks and other adaptations, as well as their more conventional and colorful cohorts, were eventually discovered and collected for scientific study, as well as for germplasm to enhance the field of horticulture, often under very physically (and financially) taxing conditions. Authoritative information on the people who strove to find these plants has been ably presented by Laurence J. Dorr, Associate Curator in the Department of Botany, in a comprehensive book entitled Plant Collectors in Madagascar and the Comoro Islands, published by the Royal Botanic Gardens, Kew in 1997. It is a landmark for being the first book published by Kew, or by a Smithsonian botanist, to be provided with an accompanying CD-ROM.
In the book one can find the biographies and itineraries of numerous well known collectors such as Wenceslas Bojer (1795-1856) who discovered Delonix regia at Foulpointe in eastern Madagascar (evidently as an introduction from the west coast by Arab settlers), and of Jacques Leandri (1903-1982) who rediscovered the delonix in its original habitat in the west at Antsingy Forest Reserve in 1932. That is the type of adventure that Dorr enjoys communicating, and his numerous papers on other figures in botanical history bear it out. Additionally, under Dorr’s own entry in the volume, we find that he was born in Boston, Massachusetts; received a B.A. from Washington University, St. Louis, Missouri (1976), an M.A. degree from the University of North Carolina at Chapel Hill (1980); and his Ph.D. from the University of Texas at Austin in 1983.
Representations of collectors in the book include several other Smithsonian botanists of the past and present who were privileged to visit Madagascar over the years, including the preeminent Pacific ecologist F. Raymond Fosberg, and W. John Kress, current Chairman of the Department. The latter’s work involved a study of the likely pollination of the traveler's tree (Ravenala) by visiting lemurs, who grasp the overlapping inflorescence-bracts with their strong hands and vigorously open them up like a farmer doing a corncob; the lemur then makes a face-first meal of the copious nectar inside the flowers. Lemur visitation is only one of the mysterious syndromes in the Madagascar flora. Another is the foot-long nectary spur of the Christmas Star orchid Angraecum sesquipedale, a species which Charles Darwin correctly predicted would be pollinated by a then-unknown moth with a foot-long proboscis (subsequently identified as the sphinx moth Xanthopan morgani subsp. praedicta). Much of the Madagascar flora is now under threat of major dismantling, and significant portions of it have been impacted to the point of obsolescence for decades by the requirements of agriculture and economic development. Fortunately, theme parks are unheard of there.
Dorr’s treatise of collectors took him ten years to write, and initially was based on his three-year period of living and collecting plants in Madagascar (1983-1986) while an assistant curator of the Missouri Botanical Garden, charged with establishing a program of research and exploration based in Antananarivo. Successfully fulfilling the mission, he went on to an appointment as a research assistant at the New York Botanical Garden (1988-1991) before arriving in the Department of Botany in the National Museum of Natural History, Smithsonian Institution in late 1991.
Too young to be embalmed by the creative sclerosis that sometimes mummifies other taxonomists, Dorr soon became interested, during and after Madagascar, in another subject of magnitude, a study of the order Malvales. Recognized in general by the mostly stellate or lepidote indumentum and the anatomical capacity to produce mucilage, relationships between the five core families (out of eight in the order) are being clarified and delimited anew through his research. With the possible exception of the Elaeocarpaceae, the major families all contain elements that are recognizable to the general public: Malvaceae (cotton, okra, Chinese hibiscus); Sterculiaceae (cacao); Tiliaceae (jute, linden tree); and Bombacaceae (baobab, durian, balsa wood). He had to lectotypify the well-known Linnean genus of the cacao tree, Theobroma, in 1993, but by and large, in order to pin down the taxonomy, nomenclature and systematics of the components of the order as a whole, Dorr frequently finds himself delving into the relations of obscurely understood tropical taxa variously ascribed to the Sterculiaceae (such as Aethiocarpa, Humbertiella, Nephropetalum), the Tiliaceae (such as Pentaplaris, Riddelia), and the Malvaceae (Nesogordonia). Convincing evidence from molecular botany and the expression of clades within the expanded Malvaceae are also being taken into consideration.
Concurrent with his efforts to advance our understanding of the Malvales, he is preparing a treatment of the flora of a very interesting 21 square kilometer area of the northern Andes Mountains, namely the Guaramacal National Park, Venezuela, on the slopes of the Sierra Nevada proper which face the llanos. Supporting around 500 genera and 1,200 species of vascular plants, already some 35 new species have been described from the area. In this enterprise, Dorr’s principal collaborator is Basil Stergios of UNELLEZ, Guanare, Venezuela, with whom he edited the recent festschrift in honor of J.J. Wurdack in the journal BioLlania (1997). A measure of Dorr’s versatility is expressed by his interest in the applications of computer technology in data processing and making scientific information available to a wider readership. To this end he was fortuitously instrumental, in 1996, in posting to the departmental world-wide web home page such items as the “Catalog of Botanical Illustrations” (with E.R. Farr and A.R. Tangerini) and the “Wood Collection, Department of Botany”, and contributed a treatment of three ericaceous genera to electronic “Neotropical Blueberries” (1998) by J.L. Luteyn of the New York Botanical Garden.
In the face of ever-diminishing natural habitats and biodiversity around the world, including some in his Guaramacal, Venezuelan study area where pristine areas are encountered less frequently every year, Dorr believes that systematic investigations of plants are, and should be, the basis of all other studies, and should be encouraged among alpha and evolutionary disciplines alike. Perhaps it is time to heed his perceptorial injunction for the new millennium.
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