Physiognomy and Structure: Physiognomically, these grasslands are generally composed of mid-height (0.5 to 1 m tall) grasses and forbs, with occasional scattered shrubs.

Floristics: Species composition varies from site to site, depending on land-use history and perhaps soil type, but in general this vegetation is quite wide-ranging in northeastern and midwestern states and at higher elevations (610-1220 m [2000-4000 feet]) in the southeastern states. Dominant grasses vary from site to site but generally include the exotic grasses Agrostis stolonifera, Agrostis hyemalis, Anthoxanthum odoratum, Bromus inermis, Bromus tectorum, Dactylis glomerata, Schedonorus arundinaceus, Lolium perenne, Phleum pratense, as well as weedy natives such as Elymus repens, Poa pratensis and, less commonly Schizachyrium scoparium. Forbs may be minor or dominant and include the exotic forbs Achillea millefolium, Cerastium arvense (and hybrids), Daucus carota, Hieracium spp., Vicia cracca, as well as weedy natives such as Ambrosia artemisiifolia, Asclepias syriaca, Euthamia graminifolia, Oenothera biennis, Potentilla simplex, Solidago altissima, Solidago canadensis, Solidago juncea, Solidago nemoralis, Solidago rugosa, Trifolium spp., Symphyotrichum lanceolatum (= Aster simplex), Symphyotrichum lateriflorum (= Aster lateriflorus), Symphyotrichum novae-angliae (= Aster novae-angliae), and many others.

A variant dominated by Phleum pratense, a native of Europe, is currently known throughout the northeastern United States and from high-elevation pastures or grass balds in the Southern Appalachians. It includes grasslands primarily dominated by alien species not native to North America, presumably originally planted or introduced by grazing animals. Vegetation of this alliance is widely distributed in the northeastern United States, as well as in montane and higher-elevation areas of the southeastern United States. Occurrences are variable and patchy, often with local dominance of tall forbs. Other characteristic species include Hieracium caespitosum (= Hieracium pratense) (alien), Potentilla canadensis, and Ranunculus acris (alien). These grasslands are maintained by periodic mowing or, in some instances, prescribed burning.

Dynamics:  These grasslands are maintained by periodic mowing or, in some instances, prescribed burning, and in other cases are succeeding to ruderal forests.