Alyssum

Alyssum simplex is a small annual herb of the family Brassicaceae, native to the Mediterranean basin and adjacent regions of southern and central Europe, North Africa, and western and central Asia, and naturalised in parts of North America and Australia. It typically grows 5–30 cm tall, with slender, erect or ascending stems branching from the base, clothed throughout with characteristic appressed stellate (star-shaped) hairs that give the plant a greyish appearance. The leaves are alternate, sessile or short-petioled, oblanceolate to narrowly elliptic, 5–20 mm long, entire, and similarly pubescent. The inflorescence is an elongating raceme of small, four-petalled flowers; petals are pale yellow, soon fading to whitish, 1.5–2.5 mm long. The fruits are small, orbicular to obovate silicles 2.5–4 mm across, flattened, with appressed stellate hairs and a short persistent style; each locule contains one or two narrowly winged seeds. The plant grows on dry, stony, sandy or disturbed ground, roadsides and field margins, and flowers from late winter to early summer.