Name:
Hydrangea arborescens / Sedum ternatum - Polypodium virginianum Cliff Shrubland
Reference:
NatureServe Biotics 2019
Description:
This association is currently known only from the Potomac River drainage in the Piedmont Triassic Basin of Virginia and Maryland and the adjacent Blue Ridge of Virginia. It occupies cliff-faces weathered from siltstone, shale, calcareous sandstone, and metabasalt. Sites subtend rivers and large streams, where progressive stream incision through resistant strata has formed escarpments of exposed bedrock. All of the documented cliffs have northerly aspects and are partly to heavily shaded by overhanging trees or trees growing in the cliff-base floodplains. Microhabitat conditions are characterized by vertical to very steep faces, with much exposed bedrock, numerous fissures and shelves, and considerable local deposition of organic-rich, colluvial soil material. Vegetation cover ranges from sparse or somewhat sparse (5-20% vascular cover) on the most massive cliffs, to moderately dense (20-50% vascular cover) on other examples. Saplings and stunted trees of <i>Fraxinus americana, Ostrya virginiana, Tsuga canadensis, Ulmus rubra, Ulmus americana, Acer saccharum, Acer nigrum, Tilia americana, Juniperus virginiana var. virginiana, Carpinus caroliniana, Quercus rubra</i>, and <i>Quercus montana</i> may occur on the cliff-faces. <i>Hydrangea arborescens</i> is a characteristic and sometimes abundant shrub, while <i>Toxicodendron radicans</i> and <i>Parthenocissus quinquefolia</i> are constant vines. Less constant shrubs include <i>Physocarpus opulifolius, Ptelea trifoliata, Hamamelis virginiana</i>, and <i>Viburnum acerifolium</i>. Characteristic herbaceous species include <i>Polypodium virginianum</i> (locally abundant), <i>Sedum ternatum</i> (locally abundant), <i>Symphyotrichum cordifolium</i> (locally abundant), <i>Dryopteris marginalis, Pilea pumila, Asplenium trichomanes, Woodsia obtusa ssp. obtusa, Aquilegia canadensis, Saxifraga virginiensis, Eurybia divaricata, Asplenium rhizophyllum, Ageratina altissima, Carex communis, Carex platyphylla, Heuchera americana, Arabis laevigata var. laevigata, Polymnia canadensis, Polystichum acrostichoides</i>, and <i>Solidago caesia</i>. Exotic weeds, including <i>Stellaria media, Lonicera japonica, Alliaria petiolata</i>, and <i>Microstegium vimineum</i>, are problematic invaders at most sites.
Accession Code:
urn:lsid:vegbank.org:commConcept:35117-{DA4CBC39-DC92-4303-AE66-D4F5E35949BD}
Plot-observations of this Community Concept:
4
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