- Name also: Stickywilly (USA, see Galium aparine)
- Family: Bedstraw Family – Rubiaceae
- Growing form: Annual herb.
- Height: 20–70 cm (8–30 in.). Stem limp, often climbing, 4-edged, rough, hook-haired, nodes hairy. Base of hooked hairs not oval.
- Flower: Corolla wheel-shaped, lime green–greenish white, approx. 1 mm (0.04 in.) broad, fused, 4-lobed. Calyx lacking. Stamens 4. Pistil of 2 fused carpels, styles 2. Inflorescence a lax, 3–9-flowered, axillary cyme.
- Leaves: Regular (actinomorphic), usually 6–9 whorled leaves; stalkless. Blade linear–lanceolate, bristle-tipped, fragile, hook-haired, with entire margins.
- Fruit: 2-parted, hook-haired or occasionally glabrous schizocarp, carpels hemispherical, 2–3 mm (0.08–0.12 in.) broad. Base of hooked hairs not swollen.
- Habitat: Fields, gardens, soil heaps, wasteland.
- Flowering time: June–September.
False cleavers arrived in Finland with people a long time ago, following agriculture as a weed all the way to northernmost Finland. It is most common in the southern third of the country, where it can be sometimes confused with its relative cleavers (G. aparine). Cleavers is a little sturdier of the two, its flowers are white, and its hooked hairs are oval at their base.
False cleavers uses its hooks to support itself on the surrounding vegetation. The hairs on its stem’s four edges are turned downwards, and those on the edges of its leaves and the central vein are recurved, while in other areas they curve forwards. The plant sticks easily to passing clothes and clings like glue: some of the hooked hairs will stick no matter which direction they are pulled from. The species’ colloquial Finnish names, which translate as e.g. tar-hay, tar-herb and twist-hay, demonstrate this property well.
After the fruit has ripened, the purpose of false cleavers’ stickiness becomes clear: the seeds travel with the part of the stem that gets ripped off and get a free ride to new habitats. The fruits are usually spiny but there is a rare subspecies (ssp. spurium) which has glossy leaves instead. It has been found growing in fields as a weed, but only several times.