Annual from 5-30 cm tall. Stem branched from the base or above. Stem and branches appressed hairy. Basal and lower cauline leaves oblanceolate, 15-70 x 4-8 mm, both surfaces covered with suberect hairs arising from a tuberculate base. Upper cauline leaves similar but smaller. Pedicels c. 2 mm long, hairy, up to 7 mm long and recurved in fruit. Calyx lobes 2-2.5 mm long, lanceolate, up to 6 mm and cordate, ± auriculate at base, nervose and with a prominent midrib. Nutlets 3-4 mm long, greyish, papillose. Style barely exserted from nutlets.