Abstract Detail



Floristics & Taxonomy

Ballard Jr, Harvey [1].

Integrative taxonomic studies of the Salad Violet (Viola edulis) species group.

In 1817, Stephen Elliott published Viola palmata L. var. heterophylla from the Ogeechee River bottomlands near Savannah, Georgia. Since then, everybody has struggled with distinguishing it from other heterophyllous violets, and interpreting its evolutionary status. Norman Russell, the last specialist to recognize it (as Viola esculenta Elliott ex Greene), provided a somewhat bizarre geographic distribution for it, and relied on foliage traits to separate it from other species. We have initiated an integrative taxonomic approach to this enigmatic violet. Our preliminary studies of herbarium specimens, fieldwork from Maryland to Georgia, and common garden observations of living plants, suggest at least four evolutionary species under the Unified Species concept. The earliest available name for the group is Viola edulis Spach, based on Elliott’s var. heterophylla. All members of the group have sharply acute eciliate sepals and prominent erose or emarginate auricles, sparsely bearded spurred petal, essentially glabrous foliage with late spring and summer leaf blades bearing three to five lobes, and cleistogamous capsules with conspicuously elongate auricles. Out of 251 specimens identified by lay taxonomists or annotated by Russell as V. esculenta, less than 30% of specimens were correctly named, whereas quite a few specimens bearing other names actually represented a member of the group. Reports from outside the Atlantic or Gulf coastal plains, and specimens taken in upland situations, were invariably other species, including glabrate-leaved phenotypes of the Viola palmata [syn.: triloba] species group, V. septemloba Leconte, and various hybrids. As we presently understand the Viola edulis group, five phenotypes are represented: a taxon with green cleistogamous capsules on tall erect peduncles, and black seeds, from the DelMarVa peninsula to South Carolina; a similar brown-seeded phenotype from southeastern Virginia south to Florida, which may be conspecific to the above; V. chalcosperma Brainerd with finely spotted cleistogamous capsules on declined peduncles, and small dark copper seeds, around Jacksonville, Florida; a taxon with heavily purple-spotted cleistogamous capsules on short prostrate peduncles, and large light brown seeds with medium-brown blotches, common in Florida but very rare westward to Mississippi; and V. langloisii Greene var. pedatiloba Brainerd, with unique leaf dissection, around Crowley, Louisiana. The name Viola edulis Spach applies to the black- or brown-seeded taxa but is not yet resolved. Future fieldwork on the Atlantic and Gulf coastal plain, and microsatellite genotyping, will aid in clarifying the diversity and distinctions of evolutionary taxa in this intriguing coastal plain violet group.


1 - Ohio University, ENVIR & PLANT BIOLOGY-PORTER H, 315 Porter Hall, Athens, OH, 45701, United States

Keywords:
integrative taxonomy
coastal plain
Viola.

Presentation Type: Oral Paper
Number:
Abstract ID:192
Candidate for Awards:None


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