Saxifragaceae (Saxifrage family)
Description: Perennial herb with a basal rosette of green to red, coarsely serrate leaves from 2 to 6 in. long, with an open inflorescence of white flowers with orange anthers. The upper 3 petals each with 2 yellow spots and the lower 2 unspotted petals readily distinguish this species when in bloom. Flowers Apr.-Aug.; fruits June-Sept.
Habitat/range: On moist to rather dry rock outcrops. Common in mountains, uncommon in piedmont. A southern Appalachian endemic from Virginia south to Georgia.
Taxonomy: A genus of about 65 species of perennial herbs of North America, South America, and Eurasia. Four of the 7 species in the mountains and piedmont are southern Appalachian endemics.
Ecology: Cliff saxifrage commonly occurs on high-elevation rock outcrops in the southern Appalachians, where it's an early colonizer of landslide scars and bare rock surfaces exposed when highways are cut through mountains (such as along the Blue Ridge Parkway). It grows in moist areas where seepage water flows over rock surfaces and on rather dry rock surfaces where plants are exposed to direct sunlight and desiccating winds. The prostrate leaves provide protection from drying winds and the semisucculent leaves, with waxy surfaces, help retain moisture. Surprisingly little is known about the ecology of this interesting plant.
Wildlife: Flies and small bees visit and pollinate the small but distinctive flowers.
Uses: Cliff saxifrage can be incorporated into rock gardens.
Synonym: Saxifraga michauxii Britton
*Microstegium vimineum (Trin.) A. Camus
Poaceae (Grass family)
Description: A sprawling annual grass 6-36 in. tall that forms dense colonies from lateral branches rooting at nodes. Leaves alternate with short, flat, lance-shaped blades 1-3 in. long with a pale silvery strip of hairs along the midrib. Flowers in narrow, terminal, spike-like racemes; fruit a tiny grain. Flowers Aug.-Oct.; fruits Sept.-Nov.
Habitat/range: Disturbed areas, including streambanks, moist woodlands, alluvial forests, forest edges, fields, and roadside ditches. Common. Native to Asia, it has become naturalized throughout the eastern United States.
Taxonomy: It's the only species of Microstegium in the mountains and piedmont.
Ecology: Japanese stiltgrass grows in habitats ranging from open to closed forests, from floodplains to uplands, and from disturbed roadsides to intact forest. Inadvertently introduced to Knoxville, Tennessee, in packing material for porcelain in the early twentieth century, it currently occurs in 25 eastern states. A harmful pest, Japanese stiltgrass ranks as one of the most destructive invasive plants in the Southeast, forming thick mats up to 3 ft. tall that can smother other herbaceous plants. Inconspicuous at first, it can replace native plant cover within 3-5 years, particularly in moist, fertile sites such as floodplains, north-facing slopes, and cove forests. It frequently invades roadsides, trails, and other disturbed areas, which then serve as satellite populations for colonizing areas in the forest interior. Even minor disturbances such as a single tree-fall provide an opportunity for colonization, after which the plant spreads rapidly by seed and by rooting at stem nodes that touch the ground. As a result, this nonnative grass can dominate large areas of the forest floor. Once established, it's difficult to eradicate as large numbers of seeds persist in the soil for years, germinating readily following soil disturbance.
Wildlife: White-tailed deer and other grazers tend to avoid Japanese stiltgrass, which gives it a competitive advantage in heavily grazed areas.
Minuartia glabra (Michx.) Mattf.
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