Habitat
New Jersey: Primarily in pitch pine lowland communities, where the water table is high and which are subject to frequent fires (every 3-10 years). Characteristic associates are Pinus rigida, Leiophyllum buxifolium, Gaulussacia frondosa, Calamovilfa brevipilis, Rhynchospora pallida. It also occurs in temporarily flooded stream ecotones, margins of forested swamps, ecotones between pine barrens and brackish marshes, wet sphagnous depressions in dry pine barrens, and (uniquely) at the upper margin of a vernal pond.
In North and South Carolina, G. autumnalis occurs in longleaf pine or pond pine communities, varying from wet pine flatwoods and wet pine savannas to mesic pine savannas, mesic pine-oak uplands, to dry (sometimes even xeric) pine-oak sandhills. Wiregrass, Aristida stricta, is a near-constant associate. The broad range of community types and moisture regimes seems to be inhabited without any particular preference. Perhaps more important is recurring fire, which reduces competition and allows germination; such fires happen every 2-10 years.
In Virginia, it historically occurred in the same habitats as in the Carolinas, but now is confined to powerlines, where the mowing or spraying (for woody species) simulates the effect of fire in reducing competition.