Oldenlandia uniflora is an annual herb, stems 10-50 cm long, erect to spreading, usually hairy, sparsely branched.
Leaves opposite, stalkless, lance-shaped, 1-2.5 cm long, margins white-hairy.
Flowers white, radially symmetrical, tubular, 0.2 cm wide, petal lobes 4, shorted than sepals; inflorescence of dense clusters, all flowers with same style length (homostylous); blooms and fruits July-Oct.
Fruit dry, densely white-hairy, below persistent sepals, seeds numerous.
Wetland status: FACW.
Frequency in NYC: Very infrequent.
Habitat: Wet open sand or soil. A coastal plain plant.