An erect, succulent, branched herb , 1 m high or less.
- Leaves: glabrous or somewhat pubescent, 3 to 5 cm long, narrowly lanceolate or oblanceolate acuminate, deeply serrate, alternate, the petioles with basal glands as seen under a magnifying glass.
- Flowers: axillary, showy, 2 to 3 cm long, usually pink, but forms with white, red, purple, or variegated petals are also found in cultivation. The sepal spur is long and slender. The stamens are 5, filaments short, broad, anthers uniting. The ovary is 5-celled, the stigma, 5-toothed, the ovules many.
- Fruits: loculicidal capsules, pubescent and explosive when ripe. The seeds are small and rounded.