SUN, FENG-JIE*, STEPHEN R. DOWNIE, AND RONALD L. HARTMAN. Department of Plant Biology, University of Illinois, Urbana, IL 61801 and Department of Botany, University of Wyoming, Laramie, WY 82071. - A phylogenetic study of Cymopterus and related genera
.
Since the early 19th century, there has been considerable
confusion concerning the proper delimitation of the genus
Cymopterus (Apiaceae; Umbelliferae) and its relationship to
putatively allied genera Aletes, Harbouria, Lomatium, Musineon,
Neoparrya, Orogenia, Pteryxia, and Shoshonea. Regarding
Cymopterus, extremes in treatment range from the recognition of
many generically distinct elements (such as, Pseudocymopterus,
Podistera, Oreoxis, Pteryxia, and Glehnia) to one large
genus with multiple subgenera and sections. Currently, some 35
species are recognized within Cymopterus. These plants are
largely endemic to western North America. They are all herbaceous
perennials, frequently caespitose and xerophytic in habit, and usually
occur in elevated habitats. Our major goal is to produce an explicit
phylogenetic hypothesis for Cymopterus using anatomical,
morphological, and molecular evidence. To date, we have obtained
sequence data from the nuclear rDNA ITS region as well as the
chloroplast rps16 intron, trnL intron, and the
trnF-trnL-trnT intergenic spacer regions. Anatomical and
morphological data have also been procured, with emphasis placed on
the taxonomically problematic species Pseudocymopterus montanus,
Pteryxia terebinthina, and Cymopterus acaulis. While our
results are preliminary, the molecular data suggest that Aletes,
Cymopterus, Lomatium, Musineon, and Oreoxis are each not
monophyletic, as currently circumscribed. The analyses of
morphological data suggest that Pseudocymopterus montanus
cannot be divided into infraspecific taxa. Moreover, the separation
of Pteryxia terebinthina varieties albiflora and
californica, and the separation of Cymopterus acaulis
varieties acaulis and fendleri, are not supported.
Key words: Apiaceae, Cymopterus, ITS, rps16, trnF-trnL-trnT, Umbelliferae