Abstract Detail

Systematics Section / ASPT

Ford, Bruce A. [2], Iranpour, Mahmood [2], Naczi, Robert F. C. [3], Starr, Julian R. [1], Jerome, Cheryl A. [2].

Phylogeny of Carex subg. Vignea (Cyperaceae) based on non-coding rDNA sequence data..

Carex subg. Vignea is a distinctive taxon (c. 300 spp., 28 sections) usually characterized by sessile, bisexual spikes, distigmatic flowers, and the lack of a cladoprophyll. Phylogenies reconstructed using rDNA ITS and ETS 1f sequences for 103 putative Vignean taxa suggest that the subgenus is monophyletic with the atypical C. gibba at its base (gynaecandrous spikes, tristigmatic flowers, cladoprophylls). This topology suggests that tristigmatic flowers and spikes, subtended by cladoprophylls, are plesiomorphic for Vignea. Four large clades distinguish the remainder of the subgenus; however, these clades do not correspond to easily defined morphological groups, with as many as six disparate sections contained within a single clade. Many traditional taxa are not upheld, while others such as sects. Ovales, Stellulatae and Glareosae are natural. Tree topologies reject the hypothesis of a gynaecandrous clade, suggesting that gynaecandry has evolved multiple times in Vignea. Species of uncertain subgeneric affinity, sometimes linked to subg. Vignea, are variously placed in our trees. For example, androgynous, unispicate species with distigmatic flowers (e.g., C. nardina, C. capitata), are members of a clade sister to Vignea, whereas dioecious, unispicate species with two stigmas (e.g., C. dioica and C. gynocrates) are nested within the subgenus. Carex fecunda, with highly compound inflorescences, distigmatic flowers and no cladoprophylls, previously linked to subg. Vignea, is positioned within a subg. Carex clade.

1 - University of Mississippi, Department of Biology, University, Mississipp, 38677, U. S. A.
2 - University of Manitoba, Department of Botany, Winnipeg, Manitoba, R3T 2N2, CANADA
3 - Delaware State University, Claude E. Phillips Herbarium, Department of Agriculture and Natural Resources, Dover, Delaware, 19901-2277, U. S. A.

Keywords:
Cyperaceae
Carex
subg. Vignea
phylogeny
ITS
ETS
non-coding rDNA sequence data.

Presentation Type: Paper
Session: 20-4
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 2:30 PM
Abstract ID:279