Texas Blackland Tallgrass Prairie

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Nature Serve ID: CES205.684


Cretaceous shales, marls and limestones, such as those of the Pecan Gap Chalk, Marlbrook Marl, Eagle Ford, Gober Chalk, and Austin Chalk Formations, and Taylor, and Navarro Groups, as well as portions of the Eocene Midway Group and Wilcox formation. Also, Miocene formations (Fleming and Oakville Sandstone formations) underlie the southern outlier of Blackland prairie recognized as the Fayette Prairie.


Flat to gently rolling and dissected by drainages, with the most significant ridges associated with harder chalk formations.


Typically Vertisols, but this system may occupy Mollisols or Alfisols in limited parts of its distribution. The system generally occurs on calcareous clays, but may also occur on loams, clay loams, or even sandy clay loams.

Parent Description

Currently, only remnants of this system exist, with most of the historical distribution replaced by crop production or improved pasture. Schizachyrium scoparium (little bluestem) is the most ubiquitous component of occurrences of this system. Andropogon gerardii (big bluestem) and Sorghastrum nutans (Indiangrass) are also common dominants. Other species commonly encountered include Bouteloua curtipendula (sideoats grama)Carex microdonta (littletooth sedge)Sporobolus compositus (tall dropseed)Nassella leucotricha (Texas wintergrass), Bothriochloa laguroides ssp. torreyana (silver bluestem), Eriochloa sericea (Texas cupgrass)Paspalum floridanum (Florida paspalum), and Tridens strictus (longspike tridens). Forbs commonly encountered in this system include Symphyotrichum ericoides (heath aster), Stenaria nigricans var. nigricans (prairie bluets), Helianthus maximiliani (Maximilian sunflower)Rudbeckia hirta (blackeyed Susan)Bifora americana (prairie bishop), Acacia angustissima var. hirta (prairie acacia), Desmanthus illinoensis (Illinois bundleflower), and many more. Perhaps more commonly encountered species include Croton monanthogynus (doveweed), Amphiachyris dracunculoides (annual broomweed), and Asclepias spp. (milkweeds). Lowland sites and swales are often dominated by Tripsacum dactyloides (eastern gamagrass) and Panicum virgatum (switchgrass).

Ecological Mapping Systems