Physiognomy and Structure: No Data Available

Floristics: Vegetation is variable in composition and cover, but generally includes mats of nonvascular plants (mosses, liverworts, and fern gametophytes) requiring high and nearly constant humidity, specialized herbs, such as Heuchera parviflora var. parviflora, Vittaria appalachiana, Thalictrum mirabile (generally rooted on the rockhouse floor), Ageratina luciae-brauniae, Solidago albopilosa, and scattered woody vines and shrubs, such as Toxicodendron radicans, Parthenocissus quinquefolia, and Decumaria barbara. Heuchera parviflora var. parviflora is the most constant indicator. Endemics, such as Ageratina luciae-brauniae and Solidago albopilosa, are associated with the floors of the rockhouses in portions of the association''s distribution, and often dominate the vegetative cover. The endemics Minuartia cumberlandensis and Silene rotundifolia sometimes occupy the floor but are more characteristic of somewhat drier sandstone exposures. Thalictrum mirabile is also endemic to this community but is more characteristic of seepages on the rockhouse walls. Scattered shrubs and tree seedlings often root in crevices, and include Kalmia latifolia, Hydrangea quercifolia, Hydrangea arborescens, Clethra acuminata, Acer rubrum, Hamamelis virginiana, and Ilex opaca var. opaca. Woody vines are often conspicuous, rooted either in crevices, in developed soil mats, or outside the rockhouse proper, and characteristically include Parthenocissus quinquefolia, Toxicodendron radicans, and (in southern portions of the association''s distribution) Decumaria barbara. Other herbs are recruited from adjacent areas, but often include Arisaema triphyllum, Eurybia divaricata (= Aster divaricatus), Athyrium filix-femina ssp. asplenioides, Medeola virginiana, Mitchella repens, Osmunda cinnamomea, Osmunda regalis var. spectabilis, Polystichum acrostichoides, Selaginella apoda, Tiarella cordifolia, Viola blanda, and Viola x primulifolia. Composition tends to be very variable from rockhouse to rockhouse, depending on the mixture of microhabitats there, the geographic location of the rockhouse, and accidents of colonization and persistence. Some noteworthy mosses in these habitats include Syrrhopodon texanus and Diphyscium cumberlandianum (D. Taylor pers. comm.).

Dynamics:  No Data Available