- Family: Bedstraw Family – Rubiaceae
- Growing form: Perennial herb.
- Height: 5–30 cm (2–12 in.). Stem limp, 4-edged, rough.
- Flower: Corolla wheel-shaped, white–greenish white, 1.5–3 mm (0.06–0.12 in.) broad, fused, 4-lobed. Calyx lacking. Stamens 4, anthers yellow. Pistil of 2 fused carpels, styles 2. Inflorescence a quite abundantly flowered terminal cyme and in upper axils.
- Leaves: Regular (actinomorphic), usually 6 whorled leaves; stalkless. Blade narrowly elliptic–oblanceolate, bristle-tipped, rough, underside hairy along central vein, with entire margin, bristle-haired.
- Fruit: 2-parted, finely granular, glabrous, brown, 1.5 mm (0.06 in.) broad schizocarp.
- Habitat: Waterside meadows, fens, spring fens, ditches, sometimes dry hillside meadows, roadsides and lawns.
- Flowering time: July–August.
The Bedstraw family has more than 13,000 members, including trees, bushes, vines and herbs, among them coffee, a tropical plant that is very familiar to Finns. A good dozen members of the genus grow wild in Finland in different places, from dry meadows to wetlands, with each species in its own habitat.
Fen bedstraw is the most common representative of the genus in Finland. It is not very demanding with regards to habitat: peat-based meadows are its most favoured habitat but also natural wetlands and springs will do. In the fells it also grows slightly higher than the tree-line. It can be found in all of Europe apart from the southern Mediterranean shore.
Fen bedstraw and marsh bedstraw (G. palustre) are quite similar at first glance as they both have the same kinds of limp stems and grow in damp places. Marsh bedstraw has a pair of leafy stipules between its stem’s opposite leaves, meaning the whorl is four-leaved; fen bedstraw’s stipules are usually divided in two, giving it a whorl of six leaves. Also, marsh bedstraw’s leaves have blunt tips with no bristle and are broader than fen bedstraw’s. Marsh bedstraw’s stem also feels glossy, while fen bedstraw’s is rough and attaches easily to e.g. passing trouser legs.