| 1 | Perennial shrubs or subshrubs |
| 1' | Annual herbs |
| 2 | Inflorescences compound, corymbose; a stout woody subshrub |
| 2' | Inflorescence a simple or very sparsely branched cincinnus |
| 3 | Petals shorter than sepals or about as long; flowers sessile or subsessile |
| 3' | Petals distinctly longer than sepals; flowers pedicellate |
| 4 | Inner sepals c. 6 mm long, thinly pilose; a slender trailing or decumbent subshrub |
| 4' | Inner sepals c. 6-9 mm long, densely white strigose along the nerves; a rather robust, sprawling or suberect subshrub |
| 5 | Inner sepals membranous, stramineous and conspicuously accrescent (and sligthly inflated) in fruit |
| 5' | Inner sepals herbaceous, not conspicuously accrescent in fruit |
| 6 | Plant with many glandular hairs; sepals obtuse; pedicels reflexed after anthesis |
| 6' | Plant pubescent or pilose; sepals acuminate or acute; pedicels erect, patent or arcuate |
| 7 | Pedicels patent or arcuate in fruit; inner sepals 4-5 mm long |
| 7' | Pedicels erect, straight and rather thick; inner sepals 8-15 mm long |
| 8 | Capsule glabrous with ciliate angles; seeds usually smooth or foveolate, or very sparsely papillose |
| 8' | Capsule pubescent, rarely glabrous except at the angles; seeds more or less densely crystalline-papillose |
