A REVISION OF THE GENUS ANTHURIUM (ARACEAE) OF MEXICO AND CENTRAL AMERICA. PART I:
MEXICO AND MIDDLE AMERICA'
Thomas B. CROAT
Anthurium (Araceae), a distinct neotropical genus with more than 700 species, is a member of the subfamily Pothoideae. The genus ranges from Northern Mexico and the Greater Antilles to Southern Brazil and Northern Argentina and Paraguay. Species diversity is greatest at lower to middle elevations of northern South America, Panama, and Costa Rica, while the upper Amazonian forests and lower Amazonian forests are relatively poor in species. In this paper, 122 species from Mexico and Middle America are revised. The 152 Panamanian species will be treated in a subsequent paper. In Mexico and Middle America, Costa Rica is richest in species, with 65. The remainder of Middle America is relatively poor in species, with Nicaragua having only 25 known species, Honduras having only 13 known species, Guatemala having 25 known species, and Belize fewer than 10 species. Mexico has 41 known taxa with 26 species endemic. In all, six new taxa from Mexico and Middle America were described in this revision: A. armeniense, A. chamulense Matuda ssp. oaxacanum, A. halmoorei, A. lancetillense, A. nelsonii, and A. rzedowskii. In addition, five new combinations have been proposed, including A. chiapasense ssp. tiaxiacense (Matuda) Croat, A. cuneatissimum (Engler) Croat, A. pedatoradiatum ssp. helleborifolium (Schott) Croat, A. schlechtendalii ssp. jimenezii (Matuda) Croat, and A. subcordatum ssp. chlorocardium (Standl. & L. 0. Wins.) Croat.
Araceae contains 110 genera and more than 2,500 species. It is worldwide in distribution but has most species in tropical areas. Its centers of distribution include both Asia and America (Croat, 1979). There are 14 genera restricted to Africa, and a few genera restricted to temperate regions of the northern hemisphere, including the Mediterranean region. Important local centers of diversity include subtropical and warm temperate South America, with eleven endemic genera, and the Indomalayan region, with thirteen endemic genera. At least 1,350 species, roughly 55 percent of the total, occur in the New World tropics and subtropics. Roughly half of these are Anthurium.
' This study was completed with support from National Science Foundation grant DEB 77-14414. The revision was based on field observations in Mexico and Central America during 1976, 1977, and 1979 and on studies in Panama since 1967. In addition, all but 12 of the 122 species are in cultivation at the Missouri Botanical Garden, and extensive observations on these living collections have been carried out. I acknowledge the assistance of D. Nicolson, who reviewed the manuscript, and of B. McAlpin, B. Virden, and H. Kamemoto, who provided critical living material. Descriptions are largely based on living collections, but descriptive data were supplemented by the extensive collections at MO and borrowed collections from A, BR, CAS, CR, F, G, H, K, M, MEXU, MICH, NY, P, DC, and US. I thank the curators of these herbaria for the loan of materials. Finally, I acknowledge the technical assistance of Frances Mazanec, Patricia Croat, Ann Ruger, and Emily Colletti.