Plants annual. Stems prostrate to ascending, branched from base, 15-20 cm, sessile. Leaves: blade ± terete, linear, 1-2 cm. Inflorescences axillary, flowers solitary, sessile or petiolate; bracts absent. Flowers 4-5 mm diam.; hypanthium obconic; calyx lobes 5, equal; petals 20, connate, white, aging yellow; stamens 10. Capsules finely papillate. Seeds 100, smooth to minutely tuberculate. 2n = 36.
Prostrate to decumbent, succulent, annual herb. Leaves almost cylindrical or slightly channelled, linear, 15-20 mm long, 2-5 mm diam., epidermal bladder-cells conspicuous. Flowers 5-10 mm diam., white or pale pink. Fruit 5-locular, valve wings reflexed and fused in pairs.
Basal leaves not forming a rosette. Like M. excavatum but leaves linear and flowers white or pinkish.
A herb. It lies along the ground. It grows each year from seeds. It is succulent.