Systematics Section / ASPT
Hilu, Khidir W. .
Distribution of Species in Grass Genera: Is It a Taxonomic Artifact?.
The grass family (Poaceae) is comprised of about 10,000 species distributed among over 700 genera and five large and a few small subfamilies. The distribution of species in genera appears skewed toward monotypic or few species per genus. This pattern follows the Hollow Curve theory proposed by J. C. Willis for various families. Explanations of the pattern have been attributed to mathematical, statistical, biological, and even psychological reasoning. The potential biological explanation for species distribution in the Poaceae is explored here. Subfamilies representing basal and terminal clades in grass phylogeny were examined, and species distribution in all subfamilies was investigated for possible correlation between genus size and age, habit and habitat. The species distribution curve is not only skewed for the number of small genera in the family but also for the total number of species in larger genera. Potential correlation between genus-richness and habit is observed and may relate to speciation via hybridization and polyploidy, both phenomena are prevalent in the Poaceae.
1 - Virginia Polytechnic Institute and State University, Department of Biology, Blacksburg, Virginia, 24061, USA
Hollow Curve theory.
Presentation Type: Paper
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 5:00 PM