Lythrum salicaria L.

Erect, often pubescent perennial 50–100 cm high. Leaves opposite, lanceolate, 2–5 cm long, slightly stem-clasping. Flowers 10–12 mm long, in a terminal leafy spike. Floral tube 5 mm long. Petals 5–6, c. 8 mm long, pink to purple or bluish. Stamens usually 12; 6 longer than the others, exserted. Widespread. Damp places. Fl. spring–summer. Purple Loosestrife