- Latin synonym: Vicia hirsuta
- Name also: Hairy Vetch, Tiny Vetch
- Family: Pea Family – Fabaceae (Leguminosae)
- Growing form: Annual herb. Taproot short.
- Height: 20–60 cm (8–25 in.). Stem (especially lower part) branched, delicate, climbing, bristly, glabrous–short-haired.
- Flower: Corolla zygomorphic, bluish white, 3–5 mm (0.12–0.2 in.) long, Petals 5; the upstanding the ‘standard’, the lateral two the ‘wings’, the lower two united to form the ‘keel’, overall shape of corolla being butterfly-like. Calyx 5-lobed, lobes longer than calyx-tube. Stamens 10, filaments with fused bases. A single carpel. Inflorescence a long-stalked, 2–5-flowered raceme.
- Leaves: Alternate, stalkless, stipulate. Blade pinnate, 5–8-pairs, terminal leaflet modified into a tendril. Leaflets linear, narrow, blunt, sharp-pointed, with entire margins. Stipules 2–4-toothed.
- Fruit: 6–10 mm (0.24–0.4 in.) long, hairy, 2-seeded pod (legume). Blackening as it ripens.
- Habitat: Cultivated land, fallow fields, flower beds, waste ground, roadsides, rocky meadows.
- Flowering time: June–October.
Hairy tare’ stems are delicate, its leaflets narrow and its flowers are almost unnoticeably small – the whole stand is like a nebulous lace curtain. The plant is very demanding with regards to the quality of the soil: at its best it appears to thrive in light peaty ground and doesn’t like heavy clay. Hairy tare has arrived in Finland with grain cultivation and grows mainly as an inconspicuous weed.
Hairy tare looks quite a lot like its close relative smooth tare (Ervum tetraspermum). Smooth tare’s flowers are slightly larger, however, (5–8 mm (0.2–0.32 in.)) and they are a darker purplish colour. There are also less of them on the raceme, often only 2 or 3. Additionally, smooth tare’s leaves have less pairs of leaflets than hairy tare. A good identification marker in the fruiting phase is smooth tare’s 4-seeded pods; hairy tare’s pods only have 2 ripe seeds. There are also some differences with regards to habitat: smooth tare likes rocky outcrops, dry meadows and waste ground, while hairy tare grows on hillside meadows and meadows close to fields and inhabited areas.