Stellaria alsine is an annual or perennial herb, small, slender, weak-stemmed, to 30 cm long, shallow, fibrous roots.
Leaves opposite, sessile or short stalked, narrow, soft, about 1.5 cm long, 0.5 cm wide.
Flowers greenish-white, very small, about 0.3 cm long, above tiny whitish bracts, usually without petals, sepals 5, green with whitish margins, narrow, tips pointed, ovary superior; inflorescence unequally branching, few-flowered; blooms May-Oct.
Fruit dry with several finely warty seeds;
Wetland status: OBL.
Frequency in NYC: Very infrequent.
Habitat: Marshes and open swamp forests, stream banks.