A NEW SPECIES OF SYMPHYOTRICHUM (ASTERACEAE: ASTEREAE) FROM A SERPENTINE BARREN IN WESTERN NORTH CAROLINA

摘要

Symphyotrichnm rhiannon Weakley & Govus, sp. nov, is described from the Buck Creek ultramafic barren (over serpentinized dunite and olivine) in the Blue Ridge province of southwestern North Carolina. It is similar to Symphyotrichum puniceum but different in its smaller stature, thinner rhizomes, subspatulate cauline leaves, narrower and fewer-headed capitulescence, phyllaries with shorter rhombic-lanceolate apical green zones, and shorter ray corollas. Its geographic range is imbedded within that oftypical S. puniceum but morphological intergrades have not been observed, despite the co-occurrence of the two taxa within several meters of one another at the type locality. The Buck Creek site is within the Nantahala National Forest; 42 hectares of thesite are managed by the United States Forest Service as a Special Interest Area and registered as a heritage area with the North Carolina Natural Heritage Program.