In New York, C. nigromarginata is found in rocky dry-mesic to mesic deciduous forests. Often these forests are of southern affinity and have oaks dominant. It is also known from coastal oak forests. Less frequently it occurs in more open rocky environments. It prefers S and E facing slopes probably because it is a southern plant at the northern edge of its range (New York Natural Heritage Program 2005). Acidic soils of rocky, dry woods, thickets, and clearings, in partial shade of mixed hardwood-pine forests or full sun along open roadsides and clearing edges, often adjacent to streams (Flora of North America 2002). Dry wooded slopes (Rhoads and Block 2000). Dry woods, chiefly in acid soils on the coastal plain (Gleason and Cronquist 1991). Dry woods, thickets, and clearings (Fernald 1970).

Acidic talus slope woodland An open to closed canopy woodland that occurs on talus slopes (slopes of boulders and rocks, often at the base of cliffs) composed of non-calcareous rocks such as granite, quartzite, or schist. Allegheny oak forest A hardwood forest that occurs on well-drained sites in the unglaciated portion of southwestern New York. This is a forest of mixed oaks with a diverse canopy and richer ground flora than other oak communities in the state. Appalachian oak-hickory forest A hardwood forest that occurs on well-drained sites, usually on ridgetops, upper slopes, or south- and west-facing slopes. The soils are usually loams or sandy loams. This is a broadly defined forest community with several regional and edaphic variants. The dominant trees include red oak, white oak, and/or black oak. Mixed with the oaks, usually at lower densities, are pignut, shagbark, and/or sweet pignut hickory. Appalachian oak-pine forest* A mixed forest that occurs on sandy soils, sandy ravines in pine barrens, or on slopes with rocky soils that are well-drained. The canopy is dominated by a mixture of oaks and pines. * probable association but not confirmed Chestnut oak forest A hardwood forest that occurs on well-drained sites in glaciated portions of the Appalachians, and on the coastal plain. This forest is similar to the Allegheny oak forest; it is distinguished by fewer canopy dominants and a less diverse shrublayer and groundlayer flora. Dominant trees are typically chestnut oak and red oak. Cliff community A community that occurs on vertical exposures of resistant, non-calcareous bedrock (such as quartzite, sandstone, or schist) or consolidated material; these cliffs often include ledges and small areas of talus. Coastal oak-beech forest* A hardwood forest with oaks and American beech codominant that occurs in dry well-drained, loamy sand of morainal coves of the Atlantic Coastal Plain. Some occurrences are associated with maritime beech forest. * probable association but not confirmed

Coastal oak-hickory forest A hardwood forest with oaks and hickories codominant that occurs in dry, well-drained, loamy sand of knolls, upper slopes, or south-facing slopes of glacial moraines of the Atlantic Coastal Plain. Coastal oak-holly forest A semi-deciduous to mixed deciduous-evergreen broadleaf forest that occurs on somewhat moist and moderately well drained silt and sandy loams in low areas on morainal plateaus. In New York State this forest is best developed on the narrow peninsulas of eastern Long Island. The trees are usually not stunted, and are removed from the pruning effects of severe salt spray. The dominant canopy trees are black oak, black gum, red maple, and American beech. American holly is abundant in the subcanopy and tall shrub layers. Oak-tulip tree forest* A hardwood forest that occurs on moist, well-drained sites in southeastern New York. The dominant trees include a mixture of five or more of the following: red oak, tulip tree, American beech, black birch, red maple, scarlet oak, black oak, and white oak. * probable association but not confirmed Successional maritime forest* A successional hardwood forest that occurs in low areas near the seacoast. This forest is a variable type that develops after vegetation has burned or land cleared (such as pastureland or farm fields). The trees may be somewhat stunted and flat-topped because the canopies are pruned by salt spray. The forest may be dominated by a single species, or there may be two or three codominants. * probable association but not confirmed Successional shrubland* A shrubland that occurs on sites that have been cleared (for farming, logging, development, etc.) or otherwise disturbed. This community has at least 50% cover of shrubs. * probable association but not confirmed Successional southern hardwoods* A hardwood or mixed forest that occurs on sites that have been cleared or otherwise disturbed. Canopy trees are usually relatively young in age (25-50 years old) and signs of earlier forest disturbance are often evident. Characteristic trees and shrubs include any of the following: American elm, slippery elm, white ash, red maple, box elder, silver maple, sassafras, gray birch, hawthorn, eastern red cedar, and choke-cherry. * probable association but not confirmed

Virginia Snakeroot (Aristolochia serpentaria) Sweet Birch (Betula lenta) Bellow-beaked Sedge (Carex albicans var. albicans) Fibrous-root Sedge (Carex communis) Slender Wood Sedge (Carex digitalis) Willdenow's Sedge (Carex willdenowii) Mockernut Hickory (Carya alba) Pignut Hickory (Carya glabra) Poverty Oatgrass (Danthonia spicata)

Bosc's Panicgrass (Dichanthelium boscii) Small-fruited Panicgrass (Dichanthelium dichotomum var. dichotomum) Whorled Loosestrife (Lysimachia quadrifolia) Common Solomon's-seal (Polygonatum biflorum) White Oak (Quercus alba) Chestnut Oak (Quercus montana) Red Oak (Quercus rubra) Black Oak (Quercus velutina)