Date of Graduation
Eberly College of Arts and Sciences
Donna I Ford-Werntz
This study incorporates morphological, anatomical, common garden and breeding system research to investigate whether Allium allegheniense and A. oxyphilum merit species status distinct from A. cernuum. Herbarium label information was recorded for 1,065 specimens and twelve quantitative and qualitative morphological traits were analyzed using univariate and multivariate techniques. The number and arrangement of scape vascular bundles was observed from nine populations (three from each species). Scapes were sectioned freehand, stained, and examined via light microscopy.;Forty-five plants of the Allium cernuum complex were collected in West Virginia and North Carolina for a common garden study to observe trait variation and phenology. To investigate the breeding system of the A. cernuum complex, a crossing experiment was performed in an insect excluded setting. Six representatives of each of the three putative taxa were arranged into two sets of nine (pollen donors and pollen recipients). Plants were also tested for apomixis and autogamy.;Allium allegheniense and A. oxyphilum were found to have discrete morphological features (primarily qualitative) that separate them from A. cernuum such that they can be recognized as the species proposed by Small (1899) and Wherry (1925). The number of scape vascular bundles ranged between 11 and 27, and the mean was higher than expected. Analysis of variance showed that vascular bundle counts alone do not distinguish the three species.;Morphological differences between the species were maintained in cultivation, although flowering periods overlapped. The flowers appeared to be outcrossing, as the open-pollinated common garden produced more seed set than the insect excluded experiment. Apomixis was not demonstrated, and a low level of self-compatibility was observed. A single putative allogamous cross was successful between A. cernuum and A. oxyphilum..;In conclusion, flower color, perianth shape and tepal apex were found to be stable in a uniform habitat such that each of the three species can be distinguished. Allium allegheniense consistently had an urceolate perianth and was purple in hue. In A. oxyphilum pedicel length was the longest and the obtuse tepals were white with a greenish midrib and base. Geographical and ecological factors likely also impact the species differentiation.
Dever, Rodney David, "Taxonomy of the Allium cernuum complex in Appalachia" (2014). Graduate Theses, Dissertations, and Problem Reports. 5484.