ALVAREZ, AIDA1,2* and KENNETH M. CAMERON1. 1The New York Botanical Garden, Lewis B. and Dorothy Cullman Program for Molecular Systematics Studies, Bronx, New York, 10458-5126; 2The City University of New York, Herbert H. Lehman College, Department of Biological Sciences, Bedford Park Boulevard West, Bronx, New York, 10468. - Systematic studies of Gomphichis (Prescottiinae, Orchidaceae).
Gomphichis is a genus of terrestrial orchids containing ca. 23
species native to the montane regions of South and Central America.
The genus is distributed in a continuum from Costa Rica to Bolivia,
with disjunct species in Guyana and southern Brazil. It is found at
high elevations between 2000-3800 m. In the most recent classification
of Orchidaceae by Dressler (1993), Gomphichis was included in
the subtribe Prescottiinae of the tribe Cranichideae along with six
other genera: Aa , Altensteinia, Myrosmodes,
Porphyrostachys, Prescottia , and Stenoptera. The
genus is poorly known and has never been monographed. Due to its
morphological resemblance to Stenoptera, the taxonomy of
Gomphichis has been problematic. Floral differences such as
the shape, size and consistency of floral segments, however, can serve
to distinguish both genera. A phylogeny generated for
Gomphichis and its allies using DNA sequences from 4
chloroplast loci (trnL-F, rbcL, atpB and
psaB) and a nuclear locus (ITS) strongly supports the monophyly
of Gomphichis and places Altensteinia as its closest
relative. Stenoptera, on the other hand, is sister to all the
remaining genera of Prescottiinae, except for Prescottia, which
is distantly related. Select morphological characters and the
evolution of unique floral features in Gomphichis will be
discussed.
Key words: Gomphichis, molecular systematics, morphology, Orchidaceae, phylogeny, Prescottiinae