morphological variation

Dr. Rebecca Hale, University of North Carolina, Asheville

Wayne Morgan, UNC Asheville Biology

Elise Powell, UNC Asheville Biology

Leila Beikmohamadi, Western Carolina University, Psychology

Mara Alexander, US Bureau of Land Management

Caroline Kennedy, UNC Asheville Biology

Jennifer Rhode Ward, UNC Asheville Biology

Pitchers of the purple pitcher plant, Sarracenia purpurea, are distinctly shorter and broader than those of other Sarracenia, which allows them to hold pools of rainwater. These phytotelma are subsequently colonized by a diverse invertebrate and microbial community, which appears to influence plant growth and reproductive effort. S. purpurea readily hybridizes with congeners to produce rosettes with morphologically intermediate pitchers, which are colonized by a similarly diverse, but less dense, community. Here, we tie together two aspects of our research investigating the ecology of hybrid pitcher plants. We show that morphology of hybrids is intermediate between that of their parent species, S. purpurea var. montana and S. jonesii (mountain sweet pitcher plant). We also show that phytotelma community diversity and number of colonists varies with pitcher morphology. Finally, we related these data to recent analyses that link phytotelma communities to plant growth and reproductive effort, and consider the implications for the conservation of cooccurring, rare pitcher plants.

Date Recorded: 
Wednesday, March 4, 2020

Hannah Cook, M.S. Candidate, Biology, Western Carolina University

Stenanthium gramineum (Ker. Gawler) Morong, commonly known as “Eastern Featherbells” is a perennial herb that occurs in the Southern Appalachians and more broadly throughout the midwestern, southwestern and eastern U.S. Historically, this species has been under-studied, and is taxonomically unclear. Currently, two varieties are recognized, distinguished in part by habitat differences. Stenanthium gramineum var. gramineum is considered a rock-outcrop species throughout its large range of the southwestern, midwestern and eastern U.S., but also occurs on grassy balds and serpentine barrens of the Southern Appalachians. Stenanthium gramineum var. robustum (S. Watson) Fernald is said to be found in bogs and wet meadows; it is listed as endangered and threatened throughout its native range of the eastern U.S., causing need for special attention. A third variety, S. gramineum var. micranthum Fernald, is not currently recognized, but was described on the basis of its unique granitic dome rock outcrop habitat. It appears to be extremely rare, and seems to be exclusive to a small range within the eastern U.S. In sum, each of these varieties occupy unique, sensitive habitat, and potentially could be recognized as separate species, as they may display discrete differences in morphological characteristics. The goal of this project was to investigate morphological and ecological characteristics of the three S. gramineum varieties in order to clarify their taxonomy and aid conservation. During the summer and fall of 2019, I located seven flowering populations of two taxa (var. gramineum and var. robustum) in the Southern Appalachians, measured morphological and environmental characters in the field and collected samples for morphological, leaf anatomical and pollen analysis. To expand the dataset, I measured multiple morphological characters on herbarium specimens from throughout the ranges of each taxon. Multivariate analysis will be performed to determine whether two or more distinct entities can be discriminated based on these data. This study should clarify the taxonomic status of var. robustum and identify the most reliable characters used to define it, and should facilitate identification and conservation of this rare taxon.

Date Recorded: 
Wednesday, March 4, 2020