PRINCE, LINDA M.* AND CLIFFORD R. PARKS. Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280. - An evaluation of tribal and generic classification of Theoideae (Theaceae) based on DNA sequence data.
The Theaceae as circumscribed by Cronquist is comprised of
approximately 40 genera and 600 species in four subfamilies. Current
classification systems of the Theoideae based on morphological and
anatomical data differ significantly in the number of genera
recognized, and in the grouping of genera into tribes and subtribes.
Our research focuses on the use of molecular data to address questions
regarding the circumscription and characterization of the genera and
tribes of the Theoideae. DNA sequences of the chloroplast
rbcLand matKgenes for representatives of most of the
ingroup taxa were used to provide an alternative evaluation of
relationships in the subfamily. While most of the genera (sensu
lato)sampled appear to be monophyletic, the data indicate a
paraphyletic Gordonia. The data provide no support for the
recognition of the genus Hartiaas distinct from
Stewartia. The close relationship between Camellia,
Pyrenaria, and Gordonia(excluding Gordonia
lasianthus) is confirmed. Cladistic analyses provide some support
for Airy-Shaw’s 1936 classification system. He recognized the
paraphyly of Gordonia, placing Gordonia lasianthusin the
tribe Gordonieae, subtribe Gordoniinae, and placing the remaining
species (as Polysporaand Laplacea)in tribe Camellieae,
subtribe Laplaceinae. Our data strongly support the recognition of
subtribes Gordoniinae and Stewartiinae as circumscribed by Airy-Shaw,
but do not adequately resolve relationships within subtribes
Camelliinae and Laplaceinae at this time.
Key words: classification, matK, molecular systematics, rbcL , Theaceae, Theoideae