A reexamination of species boundaries between Allium burdickii and Allium tricoccum (Liliaceae).

摘要

Allium burdickii and A. tricoccum , known commonly as ramps or wild leeks, are two phenetically similar taxa with similar distributions. They have been synonymized, treated as varieties of A. tricoccum, and recognized as distinct species. Because A. burdickii is reported rare and therefore tracked by conservation agencies in Appalachia, its taxonomic status is of interest. This research examined fertility and morphological relationships between the two putative species. Self-compatibility was studied by evaluating agamospermy, passive autogamy, active autogamy and geitonogamy treatments within each taxon. Interfertility was studied by comparing cross-pollination of "species" to crosses within each "species." Thirteen morphological characters from 1190 herbarium specimens were analyzed by principal components analysis and unweighted pair-group clustering. Both species were observed to be self-compatible. No significant differences were found between species except for seeds per fruit in autogamy crosses, which was significantly lower in A. burdickii than A. tricoccum, and significantly higher in hybrids than intra-taxon crosses. Due to low fruit set, additional research is needed to further elucidate interfertility. The two putative species could not be discerned by morphology and frequently exhibit characters states indicative of both taxa. Thus, the recognition of one undivided species, A. tricoccum, is supported.