- Name also: Grass-like Starwort, Grassy Stitchwort
- Family: Pink Family – Caryophyllaceae
- Growing form: Perennial herb.
- Height: 20–40 cm (8–16 in.). Stem limp–ascending, usually sparsely branched, 4-edged, glossy–rough base.
- Flower: Corolla regular (actinomorphic), white, 7–12 mm (0.28–0.48 in.) broad (sometimes only 5–6 mm (0.2–0.24 in.) on unisexual flowers); petals 5, deeply 2-lobed (looks like 10 petals), 3.5–6 mm (0.14–0.24 in.) long, usually approx. same length as calyx. Sepals 5, clearly 3-veined, with membranous margins, usually at least hairy. Stamens 10. Gynoecium syncarpous, with 3 styles. Inflorescence a 5–60-flowered, wide, lax, 2-branched cyme; subtending bracts membranous, usually with at least hairy margins at base.
- Leaves: Opposite, stalkless, spreading sideways. Blade linear–lanceolate, sharp-tipped, bright green–weakly bluish green, with entire margins, margin usually hairy at base.
- Fruit: Narrow, 6-lobed, 5–7 mm (0.2–0.28 in.) long capsule.
- Habitat: Meadows, banks, forest margins, rocky outcrops, pastures, grazing land, arable land, wasteland, roadsides, shores.
- Flowering time: June–September.
Apart from common chickweed (S. media), lesser stitchwort is the most common species of its genus in Finland, growing everywhere that there is meadow vegetation, but it is missing from natural bog and forest areas. It is so clearly fond of areas that are influenced by people that it is doubtful if it can be classed as a native plant in Finland. The species’ possible wild habitats are the upper margins of waterside meadows, semi-broadleaved hillside forest and rich rocky embankments. At least its current level of spread has only been achieved since people settled in Finland.
Lesser stitchwort grows alongside other meadow plants, but it stands out mainly on account of its abundantly flowered inflorescence. Although its solitary flower is only open for 3 days, new ones are being produced all through the summer until the beginning of September. The flower looks like it has ten petals, but actually it has only five, which are lobed almost until the base. Lesser stitchwort can even overwinter while flowering.
Lesser stitchwort can be differentiated from its close relatives by its membranous subtending bracts at the base of its inflorescence and the hairiness of its sepals. Only S. hebecalyx, which grows on the shores of Luolahti in Lake Saunajärvi in Kuhmo is hairy in the same way. This eastern species has spread with fodder to an area where Russian soldiers were encircled by Finns during WWII.