Columbus, J. Travis , Refulio-Rodriguez, Nancy F. , Chhetri, Hari .
Molecular phylogenetics of Aegopogon (Poaceae, Chloridoideae).
The taxonomy of Aegopogon has been stable for many years, although some authors have expressed uncertainty about species circumscriptions. Four species are recognized, one perennial and three annuals. Aegopogon cenchroides (perennial) and A. tenellus are distributed in both hemispheres of the New World, whereas A. bryophilus is limited to South America and A. solisii is endemic to an island off the Pacific coast of Mexico. Aegopogon is characterized by short, deciduous primary branches, each bearing three single-flowered spikelets. One of the three spikelets is larger and hermaphrodite and the other two are smaller and staminate or neuter. The group displays considerable morphological variation, especially in spikelet size, bract shape, and awn length. We estimated the phylogeny of Aegopogon by sequencing and analyzing the nrDNA ITS and cpDNA trnT–L–F regions of a large number of samples per species. Except for A. solisii, none of the species resolved as monophyletic. The nuclear and chloroplast phylogenies were concordant and comprised six main clades: two clades comprised of A. cenchroides samples, one clade of A. tenellus, one clade of A. tenellus and A. solisii, one clade of A. bryophilus, and a clade of A. bryophilus, A. cenchroides, and A. tenellus. The results clearly indicate that the taxonomy of Aegopogon requires revision. Although morphological homoplasy is clearly manifest, some variation is consistent with the phylogeny. As well, parts of the phylogeny correspond well to geography.
Log in to add this item to your schedule
1 - Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California, 91711, USA
2 - University of Washington, Department of Biology, Hitchcock Hall Rm 423, Seattle, WA, 98195-5325, USA
3 - Rancho Santa Ana Botanic Garden, Botany, 1500 N College Ave., Claremont, California, 91711, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood D/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 4:45 PM