CLARK, JOHN L. Department of Biological Sciences, George Washington University, 2023 G St. N.W., Washington, DC 20052. - Preliminary phylogeny of Alloplectus (Gesneriaceae) based on morphology and ITS sequence data.
The genus Alloplectus (Gesneriaceae) ranges from Central
America to Peru with a few species in the Lesser Antilles, but is most
diverse in western Ecuador and Colombia. Members of this genus are
herbaceous perennials that are an important component of the under
story vegetation in lowland and transitional forests throughout the
northern Andes, Central America, and lowlands of northwestern South
America. The last detailed treatment of Alloplectus was in 1865
and current studies have been limited to species descriptions.
Estimates of total diversity in Alloplectus range from 35 to 70
species. A preliminary molecular analysis utilizing ITS indicates that
Alloplectus as currently circumscribed is not monophyletic. The
currently recognized species of Alloplectus are resolved in two
distinct clades. One clade of Alloplectus species is resolved
as sister-group to Columnea and is characterized by the
presence of resupinate flowers. The other clade of Alloplectus
species is non-resupinate and groups with Drymonia.
Resupination of flowers is an important morphological synapomorphy for
Alloplectus sensu stricto that has not been previously
recognized. The non-resupinate species of Alloplectus are most
closely related to Drymonia, but taxon sampling within
Drymonia is insufficient at present to determine whether they
should be included in Drymonia or treated as a new genus.
Key words: Alloplectus, Drymonia, Gesneriaceae, systematics