Galium pusillum

Galium pusillum, commonly known as slender bedstraw or least bedstraw, is a small, tufted perennial herb of the family Rubiaceae, native to western and central Europe, where it grows on dry calcareous grassland, rocky slopes, limestone pavement and crevices in walls, particularly in upland and montane regions of the British Isles and adjacent continental Europe. The plant forms loose mats with slender, four-angled stems 5–20 cm long, ascending or decumbent, glabrous or with minute hairs along the angles. The leaves are arranged in whorls of (4–)5–6, are narrowly linear to linear-oblanceolate, 4–10 mm long and about 1 mm wide, single-veined, with a short mucronate tip and minutely serrulate margins. The inflorescence is a small terminal cyme of a few small flowers, each with a four-lobed, white, rotate corolla 2.5–3.5 mm across. The fruit is a dry, two-lobed schizocarp with finely papillose to nearly smooth mericarps about 1 mm across. The species is part of a taxonomically critical aggregate (the Galium pumilum complex) that has been variously circumscribed across its range.