Abstract Detail

Systematics Section

Simpson, Beryl [1], McDill, Joshua [1], Taylor, Sarah J. [1], Ulibarri, Emilio [2], Hansen, Debra R. [1].

Preliminary phylogeny of Adesmia (Dalbergieae:Fabaceae).

Adesmia, a genus of ca. 425 species, is restricted to the high Andean and temperate regions of South America.  Adrift as to placement for many years, it is now considered a member of the Dalbergieae clustered with several genera informally designated as the Adesmia clade.  Burkart, after working with the genus for 30 years, divided Adesmia into two subgenera, one consisting of woody shrubs and cushion plants with inflorescences that become indurated to form thorns.  He placed all of the herbaceous species in the nominate subgenus.  Within each subgenus he circumscribed numerous series, 35 in subfam. Acathadesmia and 10 in subfam. Adesmia.  Using data from several chloroplast and nuclear markers, we have been investigating the phylogeny of the genus with an eventual goal of reconstructing the speciation patterns.  Our work to date indicates that the two subgenera are not monophyletic suggesting that the thorns are not homologous within the genus.  Many of the series also do not appear to be monophyletic.  Our data show that the herbaceous species form a basal grade with most of the spiny species in a largely unresolved terminal clade.  The position of this clade in the phylogeny, combined with the short branches between its species and the geographical distribution of most of the species in the high Andes suggests a recent rapid radiation.  This conclusion is consistent with dating of a subset of species by colleagues working with the tribal phylogeny.

Broader Impacts:
This study will help to elucidate the evolutionary history of the Andean flora. We are also collaborating with colleagues in Chile and Argentina.

1 - University of Texas at Austin, Plant Resources Center and Section of Integrative Biology, 1 University Station A6720, Austin, Texas, 78712, USA
2 - Darwinion Institute, 200 Labarden, San Isidro, Bs. As., Argentina

Keywords:
Adesmia
Dalbergieae
Fabaceae.

Presentation Type: Oral Paper:Papers for Sections
Session: 10
Location: Ballroom D/Convention Center
Date: Monday, August 2nd, 2010
Time: 3:30 PM
Number: 10010
Abstract ID:257