Population Status and Habitat Description of a Rare Piedmont Perennial Herb, Marshallia legrandii Weakley (Oak Barrens Barbara’s-buttons)

Rachel Jessup^1,*, Jodi A. Forrester¹, and Lesley Starke^2,3

¹Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695. ²North Carolina Department of Agriculture and Consumer Services, Plant Conservation Program 1060 Mail Service Center, Raleigh NC 27699-1060. ³Current address - Virginia Department of Conservation and Recreation, Natural Heritage Program, 600 East Main Street, 24th Floor, Richmond, VA 23219-2094. *Corresponding author.

Southeastern Naturalist, Volume 23, Issue 2 (2024): 212–230

First published early online: 9 June 2024

Abstract
Marshallia legrandii (Oak Barrens Barbara’s-buttons) is a critically imperiled perennial herb in North Carolina and Virginia’s Piedmont region. We completed a flowering census of this species at 2 of its 3 known populations in 2021, and again at the largest of those measured populations in 2022. We compared flowering density with canopy openness at both sites. At the largest population, we also measured competing vegetation, soil properties, and Oak Barrens Barbara’s-buttons density to describe its habitat. Here, we also implemented an experimental augmentation of Oak Barrens Barbara’s-buttons to monitor planting survival and growth under different light environments. We found that Oak Barrens Barbara’s-buttons can flower under a broader range of canopy openness than previously believed. In addition to light, we found that competing vegetation, soil temperature, and soil moisture are important predictors of flowering success. Survival of augmented Oak Barrens Barbara’s-buttons was nearly 90%, and 28–42% of plants bloomed 2 years after planting.

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