Abstract Detail

Systematics Section/ASPT

Wolfe, Andrea [1], Kilkenny, Shannon [2], Zhang, Yingle [3], Blischak, Paul [4], Kubatko, Laura [5].

Species delimitation in Hyobanche (Orobanchaceae) – the H. rubra complex.

Hyobanche L. (Orobanchaceae) is a genus of holoparasitic plants native to southern Africa with most species endemic to South Africa, Lesotho and Namibia. Currently, eight species are known. Because of morphological similarities among several species and probable misidentification of many previously collected specimens, it is difficult to identify most species in the field and in museum collections. Three species, in particular, representing the H. rubra complex (H. barklyi N. E. Brown, H. glabrata Hiern, and H. rubra N. E. Brown) are very similar in morphology, have overlapping distributions, and are difficult to identify. The primary reason for this is the reduction in morphological features associated with adaptation to holoparasitism. Species of Hyobanche have rhizomes with reduced scales from which secondary haustoria arise, inflorescences that are either a fleshy compressed spike or a compact head, and flowers that are either galeate or tubular ranging in color from light pink to red or dark purple-black. The primary characters for species identification are found in the inflorescence, which is the only visible structure above ground. Preserved herbarium specimens dry black and are difficult to dissect because of the compact inflorescence. The primary goal of this study was to determine species boundaries for members of the H. rubra complex. A secondary goal was to identify morphological characters useful for species identification. Data from microsatellites and AFLP markers was collected for 210 individuals as follows: 26 individuals from three populations of H. barklyi, 94 individuals from 8 populations of H. glabrata, and 90 individuals from four populations of H. rubra. Morphometric data for 25 characters was collected from herbarium specimens and field collected accessions of all species in the H. rubra complex. Molecular and morphological data reveal close relationships among these three taxa, but clear species delimitation for H. rubra as compared to H. barklyi and H. glabrata. There are very few morphological characters useful for species delimitation in this complex. However, calyx and corolla vestiture, stigma size and extent of exsertion are useful for separating H. rubra from H. barklyi and H. glabrata. Differences between the latter two are primarily in stem bract shape and stigma size.

Broader Impacts:

1 - Ohio State University, Department of Ecology, Evolution, And Organismal Biology, 318 W. 12th Avenue, COLUMBUS, OH, 43210-1293, USA
2 - The Ohio State University, Evolution, Ecology and Organismal Biology, 318 W. 12th Ave, Columbus, OH, 43210, USA
3 - The Ohio State University
4 - The Ohio State University, Evolution, Ecology and Organismal Biology
5 - The Ohio State University, Statistics

Keywords:
Orobanchaceae
Hyobanche
species complex
species
delimitation
South Africa
holoparasite
parasitic plant.

Presentation Type: Oral Paper:Papers for Sections
Session: 49
Location: Marlborough A/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 4:00 PM
Number: 49010
Abstract ID:253
Candidate for Awards:None