A taxonomic revision of Lejeunea deplanata (Lejeuneaceae, Marchantiophyta) from tropical America
Reiner-Drehwald, Maria Elena
Lejeunea deplanata Nees was not revised since its original description and only few scattered old records were known. Study of numerous neotropical collections, including type material of Lejeunea, Rectolejeunea and Hygrolejeunea species, permitted a redescription of L. deplanata. The species is characterized by leaf lobes with a widely rounded apex often recurved, lobules from 1/4 to 1/2 the lobe length, dioicy, perianths 5-keeled, androecia with bracteoles restricted to the base of the spike and often with caducous leaves. Many poorly known taxa, namely Lejeunea leucophylla Lindenb., L. montana Gottsche, L. sabanetica Gottsche (tentatively), L. hebetata Spruce, L. megalostipa Spruce, Cheilolejeunae fissistipula Steph., Rectolejeunea longiloba Steph., Pycnolejeunea miradorensis Steph. and Hygrolejeunea paramicola Herzog, but also the often cited Lejeunea maxonii (A.Evans) X.-L.He, are proposed as new synonyms of L. deplanata. Two species from Mexico, Lejeunea chiapae X.-L.He (= Pycnolejeunea cuspidata Steph.) and Hygrolejeunea lanciloba Steph. are considered to be conspecific and to represent a variety of L. deplanata, characterized by leaf lobules with a large tooth at the apex. Lejeunea deplanata is at present known from Mexico, Central America (Costa Rica, Panama), West Indies (Dominican Republic, Jamaica) and South America [Colombia, Venezuela, Ecuador (including the Galapagos Archipelago), Peru, Bolivia]. It occurs between 1200-4000 m, except in the Galapagos Island were it is found at 200-1200 m. A description, illustrations, lectotypifications, ecological data, discussion on the variability of the species as well as differences to morphologically related taxa are presented.