Petrorhagia prolifera is an annual herb, 30-60 cm tall, sparsely branched if at all.
Leaves opposite, 1-6 cm long, to 0.2 cm wide, linear, base sheathing stem to 0.2 cm, 3-veined.
Flowers pink, radially symmetrical; petals 5, 1–1.4 cm long, tip entire or notched, 1 dark vein; calyx 5-lopbed; stamens 10; ovary superior, styles 2, 1 cm long; inflorescence small, dense, head-like, clusters of 3-7 flowers subtended by 2-6 brown egg-shaped bracts; blooms May-Sept.
Fruit a dry capsule, opening by 4 valves to release seeds less than 0.1 cm long, surface sculptured
Wetland status: UPL.
Frequency in NYC: Very infrequent.
Origin: SW Europe.
Habitat: Escaped from cultivation in disturbed habitats.
Notes: The name Petrorhagia comes from the Greek for rock fissure (Baldwin 2012).