Physiognomy and Structure: This vegetation is variable and patchy, with scattered tree saplings and shrubs, as well as graminoids and forbs.

Floristics: Species composition of this alliance includes several graminoids, of which Schizachyrium scoparium is somewhat characteristic. Other graminoids may include Agrostis gigantea, Andropogon gerardii, Carex brevior, Carex tonsa var. rugosperma (= Carex rugosperma), Cyperus lupulinus (= Cyperus filiculmis), Dichanthelium clandestinum, and Dichanthelium depauperatum (= Panicum depauperatum). The most characteristic forbs are Lupinus perennis and Polygonella articulata. Other associated forbs may include Ionactis linariifolius, Helianthemum bicknellii, Helianthemum canadense, Helianthus divaricatus, Lechea intermedia, Lespedeza capitata, and Tephrosia virginiana. The dwarf-shrub Hudsonia ericoides occurs in some examples in New Hampshire. Other scattered woody species include early-successional trees such as Betula populifolia, Populus tremuloides, and shrubs such as Comptonia peregrina, Quercus ilicifolia, and Vaccinium spp.

Dynamics:  Erosion is caused by undercutting of banks by swift currents on the outside bends of meanders. Undercutting causes slumping of banks above, and often causes deposition of turf from the terrace above. Most of the substrate is dry, but lateral seepage of groundwater may cause areas of moisture and slight nutrient enrichment.