Diodia teres is an annual herb from a taproot, often sprawling, stems 20-80 cm long, 4-sided, hairy, rough-textured, often reddish in full sun; stipules between leaf bases with 5-8 reddish bristles to 1 cm long.
Leaves opposite, 2-5 cm long, 0.6 cm wide (Yatskievych 2006), narrow, stiff, sessile, bristle-tipped,.
Flowers white-purple, axillary, radially symmetrical, tubular, petal tube 4-lobed, 0.4-0.6 cm long; in upper axillary clusters of 1-3.
Fruit eventually dry, 0.3-0.6 cm long, round, hairy, tipped by persistent sepals, splitting into two nutlets.
Wetland status: UPL.
Frequency in NYC: Infrequent.
Habitat: Open, dry sand, soil, or fill, disturbed sites.
Notes: D. virginiana found in Conference House park in a flower bed (M. Feder p.c.)