Sagina procumbens is a very small perennial herb to 10 cm, stems branching, prostrate to ascending, often matted with a dense central rosette, larger plants with small rosettes on branches.
Leaves opposite, stem leaves linear to 1 cm long 0.1 cm wide, rosette leaves to 2 cm long, bristle-tipped.
Flowers white, sepals 4 (sometimes 5), 0.2 cm, petals, shorter than sepals or none, stalks to 2 cm long; solitary or few at tips of stems or in axils; blooming April-Nov.
Fruit a capsule about equal to sepals 0.2-0.3 cm, seeds, to about half a millimeter, flattened, triangular, grooved along 2 angles, surface nubbly.
Wetland status: FACW-.
Frequency in NYC: Very infrequent (probably more common along moist sidewalks and tree pits).
Habitat: Moist open soil, shores.