San Antonio Chapter

A Rare Texas Native-Conservation of the Bracted Twistflower (Streptanthus bracteatus)

Bracted Twistflower (Streptanthus bracteatus)
Photo by Wendy Leonard

February 2024 Presentation by Wendy Leonard
A Rare Texas Native-Conservation of the Bracted Twistflower (Streptanthus bracteatus)

Explore the factors limiting the growth and distribution of a true Texas Native, the endemic Bracted twistflower (Streptanthus bracteatus).  A member of the Brassicaceae (mustard) family, S. bracteatus is a rare wildflower growing exclusively in the Edward’s Plateau ecoregion.  With less than 12 populations remaining, the species was listed at threatened in 2023.  Much of the populations that remain are experiencing decline due to a number of factors including genetic inbreeding, mismanagement of habitat, residential development, and over browsing by deer, just to name a few.  Wendy Leonard will discuss conservation efforts for Bexar and Medina Counties and the work being done to help save this species.    

Wendy Leonard has been with the City of San Antonio for 19 years.  She has a BS in Wildlife Biology and Geography: Resource and Environmental Studies from Texas State University-San Marcos and a Master’s of Science in Biology with thesis in Plant Ecology at the University of Texas at San Antonio.  Her thesis research focused on the factors limiting the growth and distribution of a rare Texas endemic wildflower. In the City of San Antonio Natural Areas, she manages native plant communities, surveys and monitors rare and endangered species and conducts research and restoration projects.  

 

View Recording of Lecture

 

To contribute to the preservation of the Bracted Twistflower, you can donate to the non-profit Imperiled Inc. by clicking on the link below:

Twistflower Preserve

 

About the Region

Fall Symposium 2025 Logo - Teach for the Future

Salado, the location of our Fall 2025 Symposium, lies at the intersection of two ecoregions: the Edwards Plateau (Limestone Cut Plain) and Blackland Prairie (Northern Blackland Prairie).

The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our fall Symposium host chapter, the Tonkawa Chapter, includes both of these ecoregions.

Source: Wildflowers of Texas by Michael Eason