Abstract Detail

Systematics Section / ASPT

Morin, Nancy [1], Ayers, Tina [2].

Intriguing southwestern endemics: characteristics and relationships of Nemacladus and Parishella (Campanulaceae s.l.).

Nemacladus and Parishella, placed by various authors in Campanulaceae, Lobeliaceae, Cyphiaceae, or Nemacladaceae, are endemic to southwestern North America. They are similar to Cyphia, found in Africa and Australia, in having fused filaments and free anthers, a condition intermediate between Campanulaceae and Lobeliaceae. Small annuals, they are remarkably diverse in flower morphology, having superior to inferior ovaries and zygomorphic to nearly actinomorphic flowers, either of which can be resupinate or non-resupinate. Primarily of arid habitats, they are found from southwestern deserts and Intermountain region to the Coast Ranges and Sierra Nevada of California, but even in high elevation areas they mostly occur in sandy desert-like microhabitats. Several species are often found in recently burned areas. Loss of most features of the very small flowers on pressed specimens and consequent reliance on seed, basal leaf, and architecture characters has resulted in widely differing classifications of the species and infraspecific taxa. Intensive field work, greenhouse observation, photography, and scanning electron-microscopy have helped characterize this interesting group. Conspicuous glands on the apex of the ovary and single-celled, finger-like projections on the filaments are not known elsewhere in any related groups. The projections are sessile or attached to a narrow or broad stipe and basal on filaments of most taxa with deeply divided corollas or median on taxa with long tubular corollas. Glands range from rounded and smooth to donut shaped and heavily papillate. Nemacladus comprises some 16 taxa, Parishella is monotypic; several taxa often occur together in mixed populations. A phylogeny based on nuclear ribosomal DNA internal transcribed spacer region suggests that suites of floral characters may have arisen independently several times, showing trends from outcrossed to selfing. More work is needed to determine the role glands, projections, resupination, corolla symmetry, connation, and patterns of nectar guides play in reproductive biology.

1 - Arboretum at Flagstaff, 4001 S. Woody Mountain Road, Flagstaff, Arizona, 86001, USA
2 - Northern Arizona University, Biology Department, Flagstaff, Arizona, 86011

Keywords:
Campanulaceae
Floral morphology
nectary
SEM
Nemacladus
Parishella.

Presentation Type: Paper
Session: 3-3
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 8:30 AM
Abstract ID:388