Evans, Timothy M. , Zuiderveen, Grady , Faden, Robert .
Phylogenetic analysis of the genus Palisota (Commelinaceae) based on chloroplast and nuclear DNA sequences.
The endemic African genus Palisota (Commelinaceae) consists of approximately 18 species. It is morphologically distinct from other Commelinaceae by several androecial and pollen characters, a fleshy berry fruit, two types of unique hairs on the vegetative parts, and a basic chromosome number (x = 20) that does not occur in any other genus in the family. Palisota appears to have diverged relatively early in the evolution of Commelinaceae, but its exact phylogenetic placement within the family is unclear and generally has low bootstrap support. Within the genus, species may have either red or blue to black fruits, and the seeds may be uniseriate or biseriate, the latter being the basis for the division of the genus into two sections Monostichos and Distichos (Clarke 1881). In our study, two chloroplast genes (matK and rbcL) and one nuclear region (AT103) were sequenced to examine phylogenetic relationships within the genus. Specific goals included: 1) determining the placement of Palisota within Commelinaceae; 2) determining the phylogenetic relationships among Palisota species; 3) examining the evolution of fruit color and seed arrangement within the genus, and 4) assessing Clarke's infrageneric taxonomy. Preliminary results place the two species with biseriate seeds, P. ambigua (blue fruit) and P. brachythyrsa (red fruit) sister to the rest of the genus. Among the remaining species in the study, all with red fruits and uniseriate seeds, P. alopecurus and P. aff. preussiana are sister to one another, and P. bogneri, P. mannii, P. satabiei, and P. bracteosa form a polytomy that is sister to P. barteri. Preliminary results thus support Clarke's sections, and suggest that fruit color may not be significant taxonomically. Sequencing in additional Palisota species is currently underway.
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1 - Grand Valley State University, Biology, 232 Henry Hall, 1 Campus Drive, Allendale, MI, 49401, USA
2 - Grand Valley State University, Biology, 1 Campus Drive, Allendale, MI, 49401, USA
3 - Smithsonian Institution, Botany, MRC-166 National Museum Of Natural History, PO Box 37012, WASHINGTON, DC, 20013-7012, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Delaware B/Hyatt
Date: Tuesday, July 10th, 2012
Time: 4:00 PM