Systematics Section / ASPT
Walker, Lia , Patterson, Robert .
Phylogenetic Systematics of Leptosiphon (Polemoniaceae) Sections Dactylophyllum and Pacificus.
Leptosiphon (Polemoniaceae) is large and morphologically diverse, and as such it has proven difficult to determine evolutionary relationships among its 30 species. Investigators have attempted to resolve these relationships using molecular data. An ITS phylogeny of Linanthus and Leptosiphon (Bell and Patterson 2000) conformed to traditional taxonomic patterns in some species groups (sects. Siphonella, Linanthus, and for the most part the long-tubed species of Leptosiphon), but varied wildly in other species groups. The wiry-stemmed pedicellate group, sect. Dactylophyllum, in fact resolved into as many as four distinct lineages within Leptosiphon. One of these lineages, consisting of L. liniflorus and L. lemmonii, plus L. grandiflorus (sect. Pacificus), formed a clade sister to the remainder of the genus Leptosiphon. This result is particularly curious because these three species are not coherent morphologically or biogeographically. Results do not support the traditionally recognized sect. Dactylophyllum as a monophyletic group, confirming that morphological features such as stem structure and inflorescence morphology are poor reflectors of evolutionary history in this group.
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1 - San Francisco State University, Department of Biology, 1600 Holloway Ave., San Francisco, California, 94132, USA
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM