STRUWE, LENA* AND VICTOR A. ALBERT. Cullman Program, The New York Botanical Garden, Bronx, NY 10458, Botanical Institute, Copenhagen University, Gothersgade 140, DK-1123 Copenhagen K, DENMARK. - Mycotrophic, non-chlorophyllous Voyria placed in Gentianaceae.
The genus Voyria (Gentianaceae) consists of 19 tropical species
of small, non-chlorophyllous and herbaceous mycotrophs. The genus
shows extensive variation in pollen morphology, stem anatomy, and
flower and seed morphology. Previous sequencing of the chloroplast
derived trnL intron for over 100 gentians and Voyria
failed to place the genus inside the family or even the order
Gentianales due to extreme sequence divergence. Several new ribosomal
18S sequences show Voyria to be placed among the basal clades
of the Gentianaceae. Nuclear ITS (internal transcribed spacer)
sequences have also been produced and will be analyzed together with
an earlier published morphological data set including all species in
the genus. The ribosomal data does not appear particularly divergent
relative to other gentians, whereas the ITS sequences differ markedly
among presumably closely related taxa. Evolution of complete or
partial mycotrophy has evolved at least three times independently in
the Gentianaceae, and this will be discussed in a phylogenetic
context.
Key words: Gentianaceae, molecular systematics, mycotrophy, phylogeny, Voyria