FREUDENSTEIN, JOHN V.1*, CASSIO VAN DEN BERGH2, W. MARK WHITTEN3, KENNETH M. CAMERON4, DOUGLAS H. GOLDMAN5, and MARK W. CHASE2. 1Herbarium and Dept. of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43212; 2Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9, 3AB, UK; 3Department of Botany, University of Florida, 220 Bartram Hall, Gainesville, FL 32611; 4The Lewis B. & Dorothy Cullman Program for Molecular Systematics Studies, The New York Botanical Garden, Bronx, NY 10458; 5L. H. Bailey Hortorium and Plant Biology, Cornell University, Ithaca, NY 14853. - A multi-locus combined analysis of Epidendroideae (Orchidaceae).
Epidendroideae comprise approximately 80% of the species of
Orchidaceae. The subfamily includes much of the variation that is
found in anther characters, traditionally the most important in orchid
classification. Simultaneous parsimony analysis of plastid rbcL, matK,
trnL-F spacer and intron, nuclear 26S and ITS, and mitochondrial
nad1b-c intron reveals support for many tribal and subtribal groups
within the family. The terrestrial tribe Neottieae is strongly
supported as sister to the remainder of the subfamily. The next
resolved clades include soft-pollinia groups, including Triphoreae,
Tropidieae, Nervilieae, and Sobraliinae, some of which have at times
been associated with other subfamilies. The "upper"
epidendroids form a monophyletic group that comprises largely
epiphytic plants with more specialized modes of pollen delivery, the
pollinia often being associated with stalks of various types. The
non-vandoid groups include many traditionally recognized subtribes,
such as Epidendreae, comprising Laeliinae + Pleurothallidinae, and a
narrowly defined Arethuseae + Coelogyninae. The higher level
associations of many of these groups are still unclear because of the
large number of short branches at the base of this clade. The majority
of vandoid orchids, those possessing an early-bending incumbent
anther, superposed pollinia, and cellular pollinium stalk, form a
well-supported clade that comprises Dressler's Maxillarieae
(monophyletic) and Cymbidieae (paraphyletic). Other vandoids comprise
the largely Old World Vandeae, sister to Polystachyinae, and
Calypsoeae. Character transformations confirmed by these patterns
include a progression from soft to hard pollinia, changes from four to
either two or eight pollinia, and shifts from terminal to lateral
inflorescences. In order to resolve the relationships of the major
clades at the base of the subfamily, which are confounded by short
branch lengths that may reflect rapid radiation, additional focused
sampling is needed.
Key words: DNA, Epidendroideae, molecular analysis, Orchidaceae, phylogeny