| 1 | Flowers blue, pink, red or white |
| 1' | Flowers yellow |
| 2 | Flowers bright red |
| 2' | Flowers blue, pink or white |
| 3 | Pedicels short, stout, not much elongating in fruit; petals pink; leaves usually more or less hairy |
| 3' | Pedicels slender, elongating in fruit; petals blue or white; leaves usually glabrous |
| 4 | Petals 7-8 mm long, pale blue; stems usually branched at base; capsule dehiscing |
| 4' | Petals 13-18 mm long, blue or white; stems usually unbranched or sparingly branched at base; capsules indehiscent or tardily dehiscent |
| 5 | Flowers small, petals less than 8 mm long; stigmas capitate or very shortly clavate |
| 5' | Flowers medium to large, petals 1 cm or more in length; stigmas clavate or almost
linear
|
| 6 | Leaves with smooth or minutely papillose margins; sepals distinctly shorter than petals; petals connate along part of their margins |
| 6' | Leaves with scabridulous margins; sepals equalling or almost equalling, or exceeding petals; petals free |
| 7 | Inflorescence a lax, open cyme with slender branches |
| 7' | Inflorescence crowded, rigid, subspicate, branches very short |
| 8 | Perennial with woody rootstock; inflorescence lax; sepals ovate, rather blunt; pedicels rather slender; gland-like stipules wanting |
| 8' | Annual; inflorescence rigid, dichotomous; sepals linear-subulate; pedicels very short; gland-like stipules present |
