Stellaria alsine, the bog stitchwort, is a species of herbaceous perennial flowering plant in the carnation family Caryophyllaceae. It grows in bogs and marshes in Europe and parts of North America.
Bog stitchwort is a rhizomatous perennial plant, with smooth, four-angled stems up to 40cm (20inches) tall.[1] Its leaves are opposite and narrow, up to 13mm long, with untoothed margins but a few marginal hairs towards the leaf-base.[1] The flowers are borne in cymes of 1–5, arising from the axils of the higher leaves. Each flower is around 6mm in diameter, with 10 stamens, 3 stigmas, five lanceolate–triangular, green-coloured but scarious-margined sepals, and five slightly shorter white petals.[1] The petals are divided into two almost to their base with the two halves angled apart,[1] so that the two halves of each petal lie over parts of adjacent sepals.[2]
Bog stitchwort grows in various types of wetland habitat; in the British Isles, it is especially characteristic of areas poached by cattle.[3] It flowers in spring and early summer.[1]
Bog stitchwort is widespread in central and western Europe, but is rarer in eastern and southern Europe and the northern half of Scandinavia.[4] It is thought to be native to eastern parts of North America, but to be an introduced species in the Pacific Northwest.[1] It has also become naturalised in South America, in Asia, where it has become a weed of rice fields,[5] and on the Kerguelen Islands in the southern Indian Ocean, where it is an aggressive invasive species.[6]
Stellaria alsine was first described by Johann Friedrich Carl Grimm in 1767.[1] The species has also been widely referred to under the junior synonym Stellaria uliginosa.[7]