Systematics Section / ASPT
Ayers, Tina , Currie, Michael W. , Morin, Nancy .
Phylogenetic analysis of Nemacladus including Parishella (Campanulaceae s.l.) based on nuclear and chloroplast sequence data.
Nemacladus (11-13 spp.) and Parishella (monotypic) are minute annuals endemic to arid environments of southwestern North America. Most species inhabit low elevation deserts to hot, dry micro sites at higher elevations in chaparral and conifer forest in the Coast Ranges and Sierra Nevada of California. Authors have placed these two genera in Campanulaceae, Lobeliaceae, Cyphiaceae, or Nemacladaceae. They are similar to Cyphia, found in Africa and Australia, in having fused filaments and free anthers, a condition intermediate to Campanulaceae and Lobeliaceae. Nemacladus and Parishella are remarkable in their diverse floral morphology, having superior to inferior ovaries and zygomorphic to nearly actinomorphic flowers, either of which can be resupinate or non-resupinate. Intensive field work and cultivation over the past two years has provided adequate material to construct a species-level phylogeny representing 28 populations of 15 taxa. A cladistic analysis of nrITS and MatK sequences divides Nemacladus into two, well-supported species groups. Parishella is sister to N. rigidus. One species group is comprised of the widespread N. gladuliferus and closely related southern species. The second group is comprised of species that span the entire geographic range although southern species are basal and northern species more derived. Nemacladus may have its origins in low elevation deserts, colonizing hot, dry microhabitats at higher elevation later in its evolutionary history. A more complete biogeographic hypothesis awaits inclusion of the remaining species and additional populations of the widespread taxa.
1 - Arboretum at Flagstaff, 4001 S. Woody Mountain Road, Flagstaff, Arizona, 86001, USA
2 - Northern Arizona University, Biology Department, Flagstaff, Arizona, 86011
Presentation Type: Paper
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 8:15 AM