A NEW SPECIES OF PTILIMNIUM (APIACEAE) FROM THE ATLANTIC COAST

摘要

Ptilimnium ahlesii Weakley & Nesom, sp. nov, is described from localities in eight counties of North Carolina, South Carolina, and Georgia in tidal freshwater marshes within 20 miles of the Atlantic coast. The species has been previously identified asP. capillaceum but differs from the latter in its conspicuously large ovaries and fruits, which at maturity are 2.7-4.2 mm long and 1.8-2.2 mm wide (vs 1.4-2.5 mm long and 0.8-1.2 mm wide in P. capillaceum), in its less-divided leaves, and in its inflorescences with fewer umbellets per umbel and fewer flowers per umbellet. The new species also flowers and fruits earlier than P. capillaceum (May-early June, late May-July, vs. mid June-early August, July-September, respectively). Ptilimnium ahlesii is rare and restricted to freshwater or slightly brackish marshes, while P capillaceum has a wider geographic range and ecological tolerance, but the two species grow in close proximity in their area of sympatry.