Systematics Section / ASPT
Simono, Scott , Rentz, Erin D. .
Systematic relationships between day- and night-blooming subspecies of Linanthus dichotomus (Polemoniaceae).
Linanthus dichotomus and L. bigelovii (Linanthus sect. Linanthus) have been traditionally distinguished by morphological features, and more recently supported by molecular data. Linanthus dichotomus is divided into two subspecies. Linanthus dichotomus ssp. dichotomus is a vespertine bloomer occurring throughout much of California south of the San Francisco Bay Area, Nevada, and Arizona. Linanthus dichotomus ssp. meridianus is a diurnal bloomer restricted to a few counties in northern California, the only diurnally blooming taxon in sect. Linanthus. Linanthus bigelovii, presumed sister to L. dichotomus, is a vespertine bloomer occurring in deserts from southeastern California to Texas. Leaf and floral features traditionally used to distinguish L. dichotomus and L. bigelovii vary greatly, and do not reliably distinguish these species. This variation, plus the two blooming regimes in L. dichotomus motivated a more detailed study of systematic relationships within sect. Linanthus. As part of a continuing systematic study of the entire genus Linanthus we focused on relationships 1) between L. dichotomus and L. bigelovii, 2) among intrasubspecific populations of L. dichotomus, and 3) between the two subspecies of L. dichotomus by examining sequence data from the ITS region of nuclear ribosomal DNA. We sampled populations of L. dichotomus and L. bigelovii from throughout California. Results confirm L. dichotomus and L. bigelovii are monophyletic sister taxa; however, our results showed enough variability between subspecies of L. dichotomus and also among intrasubspecific populations that subspecific distinction is not supported as traditionally defined. These results provide a framework to investigate relationships of biogeographic distribution, morphological variation, and reproductive biology within the L. dichotomus complex.
1 - San Francisco State University, Department of Biology, 1600 Holloway Ave., San Francisco, California, 94132, USA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM