A revision of Philodendron subgenus Philodendron (Araceae) for Mexico and Central America

Abstract

This is the first revision of Philodendron subg. Philodendron since that of K. Krause in Das Pflanzenreich in 1913. Philodendron subg. Philodendron, the largest of the three subgenera, includes 103 taxa (95 species and 8 subspecies or varieties) for Central America. Sixty-eight taxa are new to science. These include 62 species: P. albisuccus Croat, P. alticola Croat and Grayum, P. angustilobum Croat and Grayum, P. annulatum Croat and Grayum, P. antonioanum Croat, P. aromaticum Croat and Grayum, P. bakeri Croat and Grayum, P. breedlovei Croat, P. brewsterense Croat, P. brunneicaule Croat and Grayum, P. chiriquense Croat, P. chirripoense Croat and Grayum, P. clewellii Croat, P. coloradense Croat, P. copense Croat, P. correae Croat, P. cotobrusense Croat and Grayum, P. cotonense Croat and Grayum, P. crassispathum Croat and Grayum, P. cretosum Croat and Grayum, P. dodsonii Croat and Grayum, P. dolichophyllum Croat, P. dominicalense Croat and Grayum, P. dwyeri Croat, P. edenudatum Croat, P. ferrugineum Croat, P. findens Croat and Grayum, P. folsomii Croat, P. fortunense Croat, P. gigas Croat, P. granulare Croat, P. grayumii Croat, P. hammelii Croat, P. hebetatum Croat, P. heleniae Croat, P. immixtum Croat, P. jefense Croat, P. knappiae Croat, P. lazorii Croat, P. lentii Croat and Grayum, P. llanense Croat, P. madronense Croat, P. malesevichiae Croat, P. morii Croat, P. niqueanum Croat, P. pirrense Croat, P. pseudauriculatum Croat, P. purulhense Croat, P. roseospathum Croat, P. scalarinerve Croat and Grayum, P. sousae Croat, P. squamicaule Croat and Grayum, P. squamipetiolatum Croat, P. straminicaule Croat, P. sulcicaule Croat and Grayum, P. thalassicum Croat and Grayum, P. tysonii Croat, P. ubigantupense Croat, P. utleyanum Croat, P. verapazense Croat, P. wilburii Croat and Grayum, P. zhuanum; 6 infraspecific taxa: P. davidsonii Croat subsp. bocatoranum Croat, P. hederaceum (Jacq.) Schott var. kirkbridei Croat, P. ligulatum Schott var. heraclioanum Croat, P. ligulatum Schott var. ovatum Croat, P. roseospathum Croat var. angustilaminatum Croat, P. wilburii var. longipedunculatum Croat and Grayum; and 2 new combinations: P. hederaceum (Jacq.) Schott var. oxycardium (Schott) Croat, P. radiatum Schott var. pseudoradiatum (Matuda) Croat. Species diversity of P. subg. Philodendron in Central America shows a general diminution from Mexico to Middle America, followed by a marked increase closer to South America. Mexico has 21 taxa, Guatemala 15, Belize 9, El Salvador 5, Honduras 13, Nicaragua 18, Costa Rica 49, and Panama 80, respectively. Endemism is high, especially for Panama where 39 taxa are currently considered endemic. Mexico and Costa Rica each have 7 endemic species. With the exception of Belize, which has l endemic, no other country in Middle America has any endemic species. Only 26 species (28 taxa), a total of 26% of all Central American species, range into South America, 8 species (7% of the total) only to Colombia.