Glabrous annual or short-lived perennial; stems usually lax and straggling, to c. 50 cm tall, ± quadrangular, ± pink. Lvs subsessile, 8-37 × 1-9-(10) mm, linear, or linear-oblong (usually on lower part of main stems), entire but with papillate margin; base rounded, or subamplexicaul (wider main stem lvs only); apex subacute or obtuse. Fls solitary in lf axils, tristylous. Pedicels 1-1.7 mm long; bracteoles < pedicels. Calyx 5.5-7 mm long; tube narrow-obconic, tapering gradually to the narrowed base, with reddish spots about 1/2 way; lobes 0.5-1 mm long, triangular; epicalyx segments almost = lobes. Petals 6, 6-8 mm long, deep pink, crumpled; claw short; limb oblong-obovate. Stamens 12, either all ± exserted or some exserted and some included. Style 2-7 mm long, with stigma at varying levels in different plants. Mature capsule and seed not seen.