Subtribe Laeliinae (Orchidaceae) in a large and mature remnant of Brazilian Atlantic Forest

Abstract

Orchidaceae is a megadiverse botanical family in Brazil, particularly in the Atlantic Forest where it is a priority group for conservation. Parque Nacional do Itatiaia (PARNA Itatiaia) was the first conservation unit established in Brazil, and represents a large and mature remnant of Atlantic Forest. Updated data on richness, distribution and conservation of the Neotropical and ornamental subtribe Laeliinae in the park recently disclosed the occurrence of presumed locally extinct species, but without a taxonomic approach. Thus, we present a comprehensive taxonomic treatment of Laeliinae in the PARNA Itatiaia. The subtribe is represented by six genera and 33 species, which corresponds to about 15% of the orchid flora of PARNA Itatiaia. Epidendrum is the richest genus, with 20 species, followed by Cattleya (6 spp.) and Prosthechea (4 spp.). Species of Laeliinae grow in shady and humid habitats, especially near rivers, at elevations ranging 750-1,200 m, with species richness decreasing with elevation. Several species form small populations (commonly < 10 individuals), which are in need of prompt conservation actions to avoid local extinction. Samples of Laeliinae from PARNA Itatiaia in collections of consulted herbaria were found to be scarce. Variable morphological characteristics, mainly of the lip, distinguishe species of Laeliinae.