Middleton, Beth, Casey R. Williams, Chris Doffitt, and Darren Johnson. “Effects of Shading on the Rare Plant Species, Physostegia Correllii (Lamiaceae) and Trillium Texanum (Melanthiaceae)”. Journal of the Botanical Research Institute of Texas 16, no. 2 (November 29, 2022): 591–603. Accessed May 21, 2024. https://journals.brit.org/jbrit/article/view/1270.