It is an annual herb producing lightly hairy, very thin, much-branched, erect stems tall. The stem is ringed with
whorls of usually six (range four to seven) narrow linear or linear-lanceolate leaves, each a few millimetres long, and often reflexed downwards toward the stem. Each stem is topped with an open
inflorescence of many clusters of tiny greenish-white or purplish-tinged flowers. The fruit is a nutlet densely coated in slender hooked bristles. It flowers between June and August. ==Distribution and habitat==