Larson, Jason , Ballard Jr, Harvey .
A Re-evaluation of Great Lakes Taxa in North American Lycopodiella(Lycopodiaceae).
Six species of Lycopodiella (Lycopodiaceae) have been recognized to date from North America: Lycopodiella alopecuroides, L. appressa, L. inundata, L. margueritiae, L. prostrata and L. subappressa. Interspecific hybridization and substantial variation have been documented in this region, and the taxa represent diploids (most taxa), tetraploids (two Great Lakes taxa, potentially endemic, their hybrids, and reportedly, eastern L. appressa), and triploids (hybrids between diploids and tetraploids). Jim Bruce documented the existence of two tetraploids, possibly Great Lakes endemics, in his 1975 dissertation and reported hybrids between them and with the frequently co-occurring L. inundata. Unpublished phenetic studies by the second author, conducted in 1986 on mass collections from 17 southwestern Michigan Lycopodiella sites, confirmed and elaborated on Bruce's taxonomic concepts, re-identifying many herbarium specimens and Heritage Program reports of the three taxa and clarifying their distributional status. Fifteen years later (1991), Bruce, Wagner and Beitel published names for the two Great Lakes species, L. margueritiae (for Bruce's "appressed inundata") and L. subappressa ("northern appressa"), in advance of their "Flora of North America" generic treatment. However, scrutiny of the keys, protologues and specimen citations of that publication are highly heterogeneous and do not conform consistently to Bruce's original species concepts of dissertation data. Moreover, type specimens of both names disagree in diagnostic features with Bruce's original taxa and appear to represent endpoints on the continuum of variation recently detected in "robust" L. inundata, an unrecognized taxon frequent in Great Lakes coastal sites. New investigations by the first author, utilizing previous field collections and new ones made in 2010, and several major herbarium collections, are re-examining the genus in the Great Lakes and in eastern North America. We will present evidence to clarify diagnostic features, variation patterns and interspecific hybridization in the Great Lakes taxa and will contrast our taxon concepts against those currently manifested in the literature and herbarium collections.
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1 - Ohio University, Environmental And Plant Biology, Porter Hall 315, Richland Ave., Athens, OH, 45701, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell B/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 9:15 AM