Cerastium arvense is a perennial herb, stems 15- 40 cm long, hairy to smooth, branched, often forming mat at base, flowering stems usually ascending.
Leaves opposite, linear to egg-shaped, 2-7 cm long, 1-1.5 cm wide, usually with small leafy tufts in axils.
Flowers white, petals 5, deeply 2-lobed, about 1cm long, 2-3 times as long as sepals, sepals 5, to 0.8 cm long, narrow, tip pointed, styles 5, blooms April-Aug.
Fruit a cylindrical capsule, tip opening by 10 linear teeth to release numerous, rounded, almost smooth seeds.
Wetland status: UPL.
Frequency in NYC: Infrequent.
Habitat: Sandy, rocky soil, esp. on calcium rich soils, open areas, old fields. Very similar to Cerastium vulgatum, a non-native which has wider leaves with rounded tips.