Physiognomy and Structure: These glades are mosaics of patches of low-statured vegetation, including low forbs, annual grasses, and succulents. At some sites, the vegetated areas may be limited to cracks or depressions in the limestone or granitic bedrock where soil has developed and accumulated. There may be intercalated patches of dry upland and seasonally wet (or saturated) vegetation.

Floristics: The vegetation is typically dominated by low forbs, annual grasses, and succulents. Some characteristic plants on carbonate strata include Lesquerella gordonii, Lesquerella ovalifolia, Schizachyrium scoparium, Sedum nuttallianum, Sedum pulchellum, and Sporobolus vaginiflorus (var. ozarkanus and var. vaginiflorus). Nostoc commune (a cyanobacterium) is also common. At some sites, the vegetated areas may be limited to cracks or depressions in the limestone bedrock where soil has developed and accumulated. Some of the depressions hold moisture for longer periods than the surrounding landscape, providing for the establishment of a diversity of spring annuals. The dominance of the vegetation has a strong seasonal aspect. In central and western Oklahoma, examples are dominated by members of the genus Lesquerella, including Lesquerella gordonii and Lesquerella ovalifolia. Some associates include Bouteloua curtipendula, Bouteloua hirsuta, Croton monanthogynus, Mentzelia oligosperma, Oenothera macrocarpa (= Oenothera missouriensis), and Opuntia humifusa (Hoagland 2000).

On granitic materials in south-central Texas, sites contain large expanses of exposed granite surfaces, with scattered soil-filled depressions, crevices, gravel areas, and shallow pools. The vegetation is dominated by annuals and species adapted to drought conditions. Bare rock is occupied by scattered patches of crustose and foliose lichens, mosses, and several ferns and fern allies, including Cheilanthes lindheimeri, Cheilanthes tomentosa, Pellaea ternifolia, Selaginella arenicola ssp. riddellii, Selaginella peruviana, and Woodsia obtusa ssp. occidentalis. Typical species that occur in areas where shallow sand or gravel accumulate include Aphanostephus skirrhobasis, Campanula reverchonii, Helenium amarum, Hypericum gentianoides, Plantago wrightiana, Sedum nuttallianum, Phemeranthus parviflorus (= Talinum parviflorum). Areas with deeper soils are dominated by Schizachyrium scoparium occurring with other grasses such as Aristida purpurea, Bouteloua curtipendula, and Bouteloua hirsuta.

Dynamics:  In the Edwards Plateau of Texas, processes controlling this group are unclear; however, erosion likely plays a major role. Erosion may be exacerbated in some situations by removal of biomass through overgrazing. Erosion mediates the occurrence of this group through its effects on soil depth. As is true for all communities, there is a gradient from moister representatives in the east to drier ones in the west.