Abstract Detail

Floristics & Taxonomy

Chilson, Nicholas [1], Ballard Jr, Harvey [2].

Three from one: A taxonomic study of the Threepart Violet (Viola tripartita) complex.

The predominately stemmed yellow violets of Viola Section Chamaemelanium Ging. make up a lineage of 40 or more species in North America. One of the most perplexing and variable species is Viola tripartita Elliott, known commonly as Threepart Violet. Specialists have disagreed on how to taxonomically treat plants with deeply three-lobed (or occasionally five- lobed) leaf blades versus others with entire leaf blades. Some taxonomists have not distinguished these leaf morphs at all, whereas others have separated them as varieties or forms. To reevaluate potentially significant taxonomic variation in the species, numerous specimens from several major herbarium collections were examined, and macromorphological traits of the whole plant, stem and leaves were measured. Quantitative traits included the number of leaves, stem height to the lowest leaf, total plant height, lower leaf and upper leaf petiole length, descriptors of lower and upper leaf blade shape, number of marginal teeth on the lower and upper leaf blades, and number of marginal teeth on the stipules; qualitative traits categorized relative abundance of foliage trichomes, and relative abundance of marginal cilia on leaf blades. Three preliminary groups of specimens (tripartita, glaberrima and tenuipes) were readily distinguished visually, based on presence/absence of divided leaf blades, foliage color, relative length of foliage trichomes and cilia, and outline of leaf blades. Canonical variates analysis of the three a priori groups performed on the quantitative traits, and a second analysis of just the two entire-leaved groups (glaberrima and tenuipes), collectively fully distinguished all three groups and highlighted multiple whole-plant and leaf features separating the groups. Databased specimen data revealed that the three taxa nearly always inhabit separate sites and typically live on different soils and slope positions, and they maintain their distinctions in the rare occasions when they grow in the same area. All three taxa behave as separate evolutionary species and should be recognized formally as such. Viola tripartita is the rarest, often growing at higher elevations near ridgetops in the southern Appalachians. Viola glaberrima (Ging.) House grows at lower elevations over much of the eastern U.S., mostly on lower slopes not far from waterways. Viola tenuipes Pollard, resurrected from obscurity, is mostly on the southern Piedmont and Gulf Coastal Plain and replaces V. glaberrima in the Deep South.

1 - Ohio University, Department of Environmental & Plant Biology, 315 Porter Hall, Athens, OH, 45701, USA
2 - Ohio University, Department of Environmental & Plant Biology, 315 Porter Hall, Athens, OH, 45701, US

Keywords:
taxonomy
Viola
phenetics.

Presentation Type: Poster
Session: P, Floristics and Taxonomy
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PFT012
Abstract ID:939
Candidate for Awards:None