NEW OR NOTEWORTHYORCHIDS FOR THEVENEZUELAN FLORA.VII. ADDITIONS INMAXILLARIA FROM THEVENEZUELAN GUAYANA'Germdn Carnevali2 and Iv�n Ramirez2ABSTRACT Two new Maxillaria species from the Venezuelan Guayana, M. foldatsiana and M. santanae, are described andillustrated. One highly variable species, M. auyantepuiensis, is discussed, and a new subspecific taxon is proposed.Maxillaria tenuis is noted as a new record for the Venezuelan flora. Maxillaria Ruiz & Pav�n is the largest genusof the subtribe Maxillarinae, with about 400-450species ranging from Mexico and the West Indiesto southern Brazil. The genus reaches its highestdevelopment in the Andes, but Middle America,southern Brazil, the Amazonian Basin, and theGuayanas are well represented. The species ofMaxillaria usually grow in places of heavy rainfallbut often can be found in places with a markeddry season. They grow in almost every vegetationassociation and at any elevation from sea level tonear the snow line but are especially common inrainforest or cloud forests at 500-2,000 m. Mostmembers of the genus are epiphytic, but it is notunusual to find lithophytic or even terrestrial species,particularly in open, humid places. The vegetativemorphology is very variable, ranging from tinyplants less than 1 cm high to plants 2 m long.They are usually pseudobulbous, sympodial plants,but pseudobulbless, almost monopodial species arenot unknown. Rhizomes may be short, makingcaespitose plants, but many species have longcreeping primary stems; these may be appressedto substrate for their entire lengths or only attachedat their bases to the host, making erect, ascendent,or pendulous plants. Maxillaria is characterized generically by sol-itary flowers originating from the pseudobulb baseor from the internodes of the rhizome (the Cama-ridium alliance). The flowers may be minute tovery large and showy and are variable in manyrespects, although the column is always basallyproduced into a more or less well-developed col-umn-foot to which the labellum is hinged. Orni-thidium Salisb. has a rigidly attached, unhingedlabellum, and thus we feel it should be recognized,even though many authors do not do so. As amember of the subtribe Maxillarinae, ail Maxil-laria species have four dorsiventrally flattened pol-linia in two unequal pairs, more or less well-de-veloped, usually semilunate viscidium, and variouslysized and shaped stipites or no stipe at all. In Venezuela there have been recorded about75 species of Maxillaria, of which 47 are knownin the Venezuelan Guayana. All major groups with-in the genus are represented in southern Venezuela.In terms of numbers of species, Maxillaria is onlysurpassed in the Venezuelan Guayana by Pleu-rothallis R. Br. (ca. 57 species) and EpidendrumL. (ca. 51 species). The next-largest genus is Oc-tomeria R. Br. (ca. 29 species). A survey of Maxillaria species, associated withthe Orchidaceae treatment for Steyermark's Floraof the Venezuelan Guayana (Carnevali et al., in ' We are grateful to Lic. Bruno Manara for the drawings and criticisms of the Latin diagnoses and to Dr. JulianSteyermark for permitting us to use drawings originally intended for publication in his Flora of the VenezuelanGuayana. We also thank Drs. Gustavo Romero, Ernesto Foldats, Gilberto Morillo, and Angel Carnevali for theirsuggestions and critical reading of the manuscript. We are indebted to Mr. Darko Elakovich for his drawings of M.santanae. For crucial access to the orchid collection of the Herbario Nacional de Venezuela (VEN) we thank thestaff of the herbarium, especially its curators Dr. Gilberto Morillo and Lic. Libia Laskowski. 2 Jardin Botanico de Caracas, Herbario Nacional de Venezuela, INPARQUES, Apartado 2156, Caracas 1010-A,Venezuela. Current address: Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A.ANN. MISSOURI BOT. GARD. 76: 374-380. 1989.
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