Mcdade, Lucinda , Daniel, Thomas , Kiel, Carrie .
Making sense of massive polyphyly of the genus Carlowrightia (Acanthaceae: Justicieae: Tetramerium Lineage).
In our first paper on phylogenetic relationships among members of the Tetramerium lineage (Acanthaceae:Justicieae; Daniel et al. 2008. Syst Bot 33: 416-436), we reported a number of results that were not congruent with existing taxonomic treatments of these plants. This was especially true of New World plants among which only a single non-monospecific genus was shown to be monophyletic with strong support (i.e., Tetramerium). Even in this context, Carlowrightia, a genus of 26 species (12 sampled for the earlier study) was noteworthy, with species placed in three different clades. More recently, with the goal of understanding the evolutionary history of the genus as a whole, we have added six additional species (carefully chosen to encompass morphological diversity and the geographic range of the genus). Analysis of a data set of nearly 4500 bps confirms results for the 12 previously sampled taxa and places some of those newly sampled as expected based on morphological characters. In contrast, three of the newly sampled taxa are placed in two new clades. Argentinian C.sulcata is part of a clade referred to as the South American Anisacanthus clade in our earlier paper, adding support to the notion of a geographic signal among these plants. Two Chihuahuan desert species, C. parvifolia and C. albiflora are placed with monospecific Gypsacanthus which shares the same habitat. Plants of species of Carlowrightia vary markedly in corolla morphology (from subactinomoprhic to pseudopapilionaceous) and also in seed morphology; patterns of variation in these traits are mostly congruent with our new phylogenetic results albeit with some notable exceptions.
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1 - Rancho Santa Ana Botanic Garden, Department Of Botany, 1500 N. College Avenue, Claremont, CA, 91711, USA
2 - California Academy of Sciences, Department of Botany, 55 Music Concourse Drive, Golden Gate Park, San Francisco, CA, 94118, USA
3 - Rancho Santa Ana Botanic Garden, 1500 North College Ave., Claremont, CA, 91711, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell B/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 2:45 PM