Knox, Eric B. .
Evolution of Wimmerella (Lobeliaceae).
The segregate genus Wimmerella Serra, M.B. Crespo & Lammers was erected 10 years ago to accommodate 10 South African species of Lobeliaceae previously assigned to the polyphyletic (and illegitimate) genus Laurentia Adans. The tubular corolla of Wimmerella readily distinguishes these species from Lobelia (the ‘core’ genus of the Lobeliaceae), in which the corolla is split to the base along the back. One subgroup of Wimmerella occupies moist, open sites, whereas the other subgroup grows in caves or below overhanging rocks, and there are numerous morphological differences that distinguish these two groups. Analysis of initial chloroplast DNA sequence data placed another South African species (Lobelia anceps L.f.) sister to representatives of the open-site group, which raised the question: Did these two groups evolved independently from a Lobelia ancestral lineage? Complete taxonomic sampling demonstrates that the cave-dwellers evolved from the open-site group, as did L. anceps, which apparently reverted to a Lobelia-like floral morphology. Specimen comparisons indicate that W. giftbergensis (E. Phillips) Serra, M.B. Crespo & Lammers is a synonym of W. bifida (Thunb.) Serra, M.B. Crespo & Lammers, but the latter name was historically misapplied to diminutive individuals of W. arabidea (C. Presl) Serra, M.B. Crespo & Lammers. Two new species of cave-dwelling Wimmerella were discovered, and it is likely that additional undescribed species grow in remote caves scattered on the mountains of the Western Cape.
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1 - Indiana University, Department of Biology, Jordan Hall 142, Bloomington, Indiana, 47405, U.S.A
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood D/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 9:45 AM