Abstract Detail

Floristics & Taxonomy

Ballard Jr, Harvey [1].

Delineating evolutionary species and defining species groups in the Acaulescent Blue violets (Viola Subsection Boreali-Americanae, Violaceae).

The Acaulescent Blue violets, Viola Subsection Boreali-Americanae (W.Becker) Brizicky, have weathered a torturous taxonomic history over the last 125 years. Frequent interspecific hybridization, apparent within-species polymorphism, and purported phenotypic plasticity have been invoked as major challenges to taxonomic delineation. Ezra Brainerd and Nir Gil-ad utliized structures and traits over the entire plant body to delineate taxa, whereas Norman Russell and Landon McKinney relied almost exclusively on foliage traits to distinguish taxa. Brainerd went further in cultivating populations for multiple generations in a common garden and observation fertility and reproductive behavior, separating consistent and uniform taxa from de novo hybrids, whereas Gil-ad employed micromorphological traits of seeds and lateral petal trichomes as proxies for genetic evidence of interspecific hybridization. Not surprisingly, these specialists arrived at widely different classifications of taxonomic diversity, from 10 species and six infraspecif taxa by McKinney to 30 species and three infraspecific taxa by Brainerd. In our integrative taxonomic reevaluation of the Acaulescent Blue violets we conduct intensive field studies; consult local, regional and national herbarium collections; cultivate representatives of populations and taxa in a common garden to observe genetically fixed spring and summer morphological features and reproductive behavior; determine soil factors; document genetic differentiation from microsatellite loci (limited to certain complexes); and delineate taxa using statistical tests. We interpret and delineate evolutionary species through the objective filter of the Unified Species Concept. We have thus far delineated 45 distinct evolutionary species and one variety, including nine new species (133-275% of taxa recognized by previous specialists). Our investigations urge further study of 13 anomalous phenotypes as potential additional species. We have tentatively grouped taxa into nine loose morphologically and ecologically defined species groups for convenience. Species groups and representative species are introduced, and some of the new species and anomalous taxa under scrutiny are highlighted.

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

Keywords:
Viola
Acaulescent Blue violets
integrative taxonomy
species delimitation
Unified Species concept
new species.

Presentation Type: Oral Paper
Session: FT, Floristics & Taxonomy
Location: Tucson J/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 1:30 PM
Number: FT001
Abstract ID:388
Candidate for Awards:None