Physiognomy and Structure: The vegetation included in this macrogroup is evergreen shrub-dominated. Some associations may have widely scattered needle-leaved trees. The vegetation may vary in height depending on the fire-return interval. The habitats are influenced by high water tables and organic soils.

Floristics: The vegetation of this macrogroup is typically found in large wetlands called pocosins. The communities have in common a dense shrub layer of wetland shrubs tolerant of the organic soils, low nutrient conditions, and fire. Arundinaria tecta (= Arundinaria gigantea ssp. tecta), Cyrilla racemiflora, Ilex coriacea, Ilex glabra, Lyonia lucida, Lyonia mariana, Morella cerifera (= Myrica cerifera var. cerifera), Symplocos tinctoria, and Zenobia pulverulenta are characteristic and usually dominant in some combination, along with Smilax laurifolia. Pinus serotina is the characteristic tree, and it along with a set of evergreen hardwoods, including Gordonia lasianthus, Magnolia virginiana, and Persea palustris, are generally the only trees present. Under pre-European settlement fire regimes, stands of Arundinaria tecta (canebrakes) would have been more common and extensive. Component communities tend to be low in plant species richness, and woody species richness exceeds herbaceous in most associations, with herbs being limited to small open patches. Some herbs may include Woodwardia virginica and Carex striata var. striata. The physiognomy, in terms of vegetation height and density, is variable, depending on fire history, and can vary from densely shrubby to herbaceous. In current condition, most examples are shrubby, but may have scattered trees.

Dynamics:  Under current conditions, the vegetation is predominantly dense shrubland. Herbaceous plants are present only as small patches. Vegetation is typically zoned. The vegetation of pocosins is zoned, with the lowest statured vegetation in the center, with woodlands on the edges and in the smaller occurrences. Under pre-European settlement fire regimes, stands of Arundinaria tecta (canebrakes) would have been more common and extensive. Fire is an important factor in these systems, with the pre-settlement fire regime probably being very different from that observed under current conditions. Natural fire-return intervals are not well-known, but are probably on the order of one to five or more decades in the wettest areas. Peripheral areas may be subject to fire as often as the surrounding vegetation burns, which may naturally have been an average of 3 years. Fires are typically intense due to density and flammability of the vegetation, killing all above-ground vegetation. They are followed by vigorous root sprouting by shrubs and hardwoods, leading to recovery of standing biomass within a few years. Pinus serotina recovers by epicormic sprouting or by regeneration from seeds released from serotinous cones. Fires during droughts may ignite peat, forming holes that take longer to recover. Herb-dominated openings in pocosins may depend on peat fires, though this is not well-documented. Natural fires occur in large patches, creating a shifting patch structure that interacts with the vegetational zonation created by peat depth. The intensity of fire in these systems makes fire control difficult; prescribed burning is seldom done, and wild fires continue to be a significant influence. The larger peatlands are believed to have been created by paludification following natural blocking of drainage (Otte 1981). Peat buildup raises the water table in the center, creating the domed structure of the largest peatlands and allowing the wetland to spread out as wetness is increased at the edges. Deeper pocosin peats contain fossil logs that indicate dominance by a swamp forest in past millennia. Otte (1981) noted that peat fires likely limit the height to which the peat can accumulate, in proportion to how high it can raise the local water table. The dominance of mostly broadleaf evergreen shrubs as opposed to a canopy of deciduous hardwoods distinguishes this macrogroup from nonriverine swamp forests.