| 1 | Bracteoles 2, inserted on calyx-tube; corolla blue, pale lilac-blue, mauve, purple or violet; stem usually branched |
| 1' | Bracteoles absent; calyx 2-cleft; corolla whitish, yellowish, brownish, reddish or maroon, sometimes tinged violet or purple; stem normally unbranched |
| 2 | Corolla-tube not markedly constricted above ovary |
| 2' | Corolla-tube markedly constricted above ovary |
| 3 | Bracts caudate-acuminate, far overtopping buds at apex of inflorescence; corolla-lobes of lower lip 2.0-2.5 mm long; plant robust, 18-40 cm high |
| 3' | Bracts not markedly caudate-acuminate; corolla-lobes of lower lip 4.0-4.5 mm long; plant 10-15 cm high |
| 4 | Corolla 20-30 mm long; tube 6-10 mm wide at apex |
| 4' | Corolla 12-20 mm long; tube 4-5 mm wide at apex |
| 5 | Corolla-lobes tapering, acute (hosts: Helichrysum, Phagnalon) |
| 5' | Corolla-lobes ovate, more or less obtuse |
| 6 | Stems usually with 3-9 or more branches; inflorescence usually rather lax, elongate; corolla-tube 12-15 mm long |
| 6' | Stems unbranched or sparingly branched; inflorescence compact, rather congested; corolla-tube often more than 15 mm long |
| 7 | Corolla-tube c. 4 mm wide at apex, maroon-red; corolla-lobes finely fimbriate-denticulate; inflorescence compact, crowded |
| 7' | Corolla-tube 5-10 mm wide at apex, not maroon-red |
| 8 | Calyx-divisions entire; corolla with 2 conspicuous yellow folds on lower lip |
| 8' | Calyx-divisions deeply 2-lobed |
| 9 | Corolla-tube indistinctly curved, 10-15 mm long; corolla-lobes conspicuous, spreading, the adaxial 7-12 mm wide |
| 9' | Corolla-tube distinctly curved throughout its length, 8-10 mm long; corolla-lobes inconspicuous, the adaxial porrect, the others spreading |
| 10 | Corolla-tube subglabrous or shortly glandular-pubescent dorsally |
| 10' | Corolla-tube with white, flattened, crispate hairs dorsally |
