Southeastern Great Plains Tallgrass Prairie

Geology

Lower Cretaceous formations, including various limestones, sands (such as from the Paluxy and Antlers formations), and clays (such as from the Walnut formation).

Landform

In contrast to Blackland Prairie, surfaces are flat rather than undulating, and valley slopes are angular rather than rounded. The "cuesta" landforms with gentle slopes leading up to relatively abrupt escarpments are characteristic of this portion of the Southeastern Great Plains Tallgrass Prairie

Soils

Soils of the Southeastern Great Plains Tallgrass Prairie in Texas differ from those of the Southern Blackland Prairie in being browner in color and containing more rock fragments, though much of the region occupied by this prairie is included in the Blackland Ecological Site. Clay Loam, Sandy Loam, Shallow, and Claypan Prairie are also significant Ecological Sites for this system. Soils of this area are more frequently characterized as Mollisols, as opposed to the Vertisols more characteristic of the Blackland Prairie. Calcareous clays are commonly encountered.

Parent Description

Schizachyrium scoparium (little bluestem) tends to dominate sites of this system, with Bouteloua curtipendula (sideoats grama) as another significant component. Other grasses that are frequently present include Nassella leucotricha (Texas wintergrass), Bothriochloa laguroides ssp. torreyana (silver bluestem), Aristida spp. (threeawn), Andropogon gerardii (big bluestem), Buchloe dactyloides (buffalograss), Sporobolus compositus (tall dropseed), Bouteloua hirsuta (hairy grama), Sorghastrum nutans (Indiangrass), Muhlenbergia reverchonii (seep muhly), Chloris verticillata (tumble windmillgrass), and Erioneuron pilosum (hairy tridens). Forbs species such as Symphyotrichum ericoides (heath aster), Ambrosia psilostachya (western ragweed), Tragia ramosa (catnip noseburn), Amphiachyris dracunculoides (common broomweed), Dyschoriste linearis (narrowleaf dyschoriste), Salvia texana (Texas sage), Oenothera spp. (evening primrose), Stenaria nigricans var. nigricans (prairie bluets), Lindheimera texana (Texas star), Thelesperma spp. (greenthread), Dalea spp. (prairie clover), and Psoralidium spp. (scurfpea) may be encountered. Occurrences often contain and are sometimes dominated by the non-native grass Bothriochloa ischaemum var. songarica (King Ranch bluestem) and/or Cynodon dactylon (Bermuda grass). Significant areas of this system remain within the Grand Prairie of Texas.