Monfils, Anna , Fleming, Samantha , Lichtenwald, Samantha , Shiels, Derek , Blum, Michael .
Evolution and diversity in the Schoenoplectus pungens species complex (Cyperaceae).
The Schoenoplectus pungen species complex is characterized with a high level of morphological similarity among species and frequent hybridization. Descriptions of species and varieties in the complex overlap in character states, confounding practical identification. Hybridization, prevalent in the group, has led previous authors to question the integrity of individual species and variety descriptions. The study presented here undertook a comprehensive molecular and morphological investigation of species and varieties in the S. pungens species complex (including S. americanus, S. deltarum, S. pungens var. pungens, S. pungens var. badius, and S. pungens var. longispicatus) to evaluate diacritical characters for species and variety boundaries, determine integrity of species and variety descriptions, and resolve the origin of S. deltarum. We assessed potential diacritical morphological characters including awn length and coloration, culm morphology and diameter, bract length, stigma lobe number, distal leaf blade length and spikelet number from 36 populations and up to 1000 specimens from throughout North America. DNA sequence variation of the nuclear ITS and chloroplast trnTLF regions were analyzed for all species, varieties and potential hybrid combinations. Additional studies of genotypic differentiation were assessed within and among S. pungens, S. americanus and S. deltarum using microsatellite data. Awn length, stigma lobe number, distal leaf blade length, culm diameter and morphology, and spikelet number were identified as key morphological feature for species and hybrid identification. Awn coloration delineated S. pungens var. badius from other varieties. Molecular sequence data indicated clear genotypic differences between S.americanus and all other members of the complex. Microsatellite data indicated S. deltarum is a distinct entity in comparison to S. pungens and S. americanus, and S. deltarum and S. pungens are more closely related to one another than either is to S. americanus. Results from these analyses provide clear characters and molecular evidence for species differentiation, help resolve the origin of S.deltarum, and facilitate the examination of the varietal status within S. pungens.
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1 - Central Michigan University, Biology Department, 180 Brooks Hall, Mount Pleasant, MI, 48858, USA
2 - Central Michigan University, Biology Department, 217 Brooks Hall, Mount Pleasant, MI, 48858, USA
3 - Tulane University, Dept of Ecology & Evolutionary Biology, New Orleans, LA, 70118, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell A/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 10:45 AM