Dyer's Greenweed

In Great Britain and/or Ireland:
Foodplant / parasite
conidial anamorph of Erysiphe trifolii parasitises live Genista sibirica

When you see dyer's greenweed blossom, you know the summer has begun. However, you will not find this plant in many places in the Netherlands. Texel, Terschelling and Ameland are the best growing areas for dyer's greenweed. It grows in calcium-poor dune valleys. Although there are lots of possible soils for it to grow, it is a rare species that is declining strongly due to human influence: it is very sensitive to intensive grazing and fertilization. Dyer's greenweed was used as a dye in earlier times, which explain's its name.

Perennial, Shrubs, Woody throughout, Taproot present, Nodules present, Stems erect or ascending, Stems or branches arching, spreading or decumbent, Stems less than 1 m tall, Stems 1-2 m tall, Stems solid, Stems or young twigs glabrous or sparsely glabrate, Leaves alternate, Stipules conspicuous, Stipules green, triangulate to lanceolate or foliaceous, Stipules persistent, Stipules free, Leaves simple, or appearing so, Leaf or leaflet margins entire, Leaflets 1, Leaves glabrous or nearly so, Flowers solitary in axils, or appearing solitary, Flowers in axillary clusters or few-floweredracemes, 2-6 flowers, Inflorescences racemes, Inflorescence axillary, Bracts conspicuously present, Bracteoles present, Flowers zygomorphic, Calyx 2-lipped or 2-lobed, Calyx glabrous, Calyx hairy, Petals separate, Corolla papilionaceous, Petals clawed, Petals orange or yellow, Banner petal ovoid or obovate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Stamens 9-10, Stamens or anthers dimorphic, alternating large and small, Stamens monadelphous, united below, Filaments glabrous, Anthers versatile, Style terete, Style sharply bent, Fruit a legume, Fruit unilocular, Fruit freely dehiscent, Fruit elongate, straight, Fruit oblong or ellipsoidal, Fruit exserted from calyx, Fruit glabrous or glabrate, Fruit 3-10 seeded, Seeds ovoid to rounded in outline, Seed surface smooth, Seeds olive, brown, or black.

Genista tinctoria, the dyer's greenweed or dyer's broom, is a species of flowering plant in the family Fabaceae. Its other common names include dyer's whin, waxen woad and waxen wood. The Latin specific epithet tinctoria means "used as a dye".