1Corolla hidden in basal part of the calyx tube, minute (2-3 mm long). Flowers cleistogamous. Calyx bilabiate; upper lip much broader than the teeth of lower lip, its margins decurrent along the tube
1'Corolla exserted from the calyx. Flowers chasmogamous.
2Flowers spirally arranged along the rachis of very dense, 2-15 cm long, simple spikes, 1.5-2 cm long, blue. Bracts during anthesis exceeding the calyx, very conspicuous at the tops of the spikes, brown, acutely acuminate, long-ciliate. Calyx below the apical margin of the short tube with 5 equal, c. 0.5 cm long, at first filiform, afterwards spinous teeth, alternating with 5 minute toothlets, finally closed at the top. Leaves linear-lanceolate, sharply serrate, ± sessile. Cultivated.
2'Flowers pale yellow in axillary long-peduncled (6-8 cm), dichotomously branched, straight, many-flowered cincinni. Long-soft-hairy short plant with a soft-woody, prostrate stem less than 10 cm long, and crowded large leaves 15-20 by 10-12 cm; internodes c. 0.5 cm
2''Otherwise. Flowers in verticillasters or in cymes, these with or without well-developed rachises, often combined into spurious heads, spurious spikes, racemes, or panicles.
3Perfect stamens 2; connective usually filiform; if not, then the plant finely stellate-hairy.
3'Stamens 4 but only the upper pair perfect; anther-cells divaricate. Calyx 2-lipped. Verticillasters 2-flowered, secund, spaced, in racemes. Corolla almost actinomorphic, hardly 2-lipped.
3''Perfect stamens usually 4; if fewer, then the plant not stellate-hairy, nor the connective long-filiform.
4Filaments short, not toothed; connective transverse to the filament and articulate with it, versatile, long-filiform; its anterior part erect under the upper lip, bearing a single well-developed, often linear perfect anther-cell; its posterior part stuck into the throat, never bearing a perfect anther-cell, but sometimes with effete malformed one. No stellate hairs
4'Connective otherwise, the two anther-cells not separated in this way.
4''Otherwise again.
5Leaves rather approximate, subsessile, linear-lanceolate, with recurved, entire margins, rigid, finely stellate-hairy, 1.5-3.5 cm by 1.5-4.5 mm. Cultivated.
5'Leaves well-spaced, petioled, not stellate-hairy, rhomboid to ovate, 1-2 by 0.5-1 cm; margin flat, toothed
6Lower verticillasters wide apart, axillary. Corolla red; upper lip entire, densely pilose. Calyx 10-ribbed. Corolla tube slightly shorter than the calyx; 2 anterior stamens longest. Nutlets cuneate-trigonous, truncate, brown. Plant not lemon-scented
6'At least the medium and lower leaves deeply palmatifid or pinnatifid. Calyx teeth in normal flowers 5, subequal, rarely 6-7. Stamens covered by the upper lip. Style arms subequal. Disk equal-sided.
6''Leaves much less deeply or not divided. 87a. Verticillasters combined into a terminal head or dense spurious spike. Corolla white; upper lip tinged with red, deeply bipartite. Calyx 13-15-nerved. Corolla tube exceeding the calyx; 2 posterior stamens longest. Nutlets ovoid, black. Plant lemon-scented when bruised. Cultivated.