Perennial herb. Stems erect, 30-60 cm, quadrangular, not or little branched, glabrous or with very short eglandular hairs. Leaves linear-lanceo- late or linear-elliptic, up to 80 x 10 mm, firm-textured, glabrous on adaxial surface, abaxially glabrous, with a scattered pilose or ± dense eglandular indumentum and with some sessile oil globules, entire to finely serrulate, truncate to acute, nervation prominent below. Petiole absent to c. 3 mm. Inflorescence a short or elongated congested spike, 20-70 x 15-25 mm. Outer bracts broad ovate acuminate, usually purplish; inner bracts linear, ciliate, as long as calyces. Pedicels subabsent. Calyx thin-textured, 6-10 mm, narrow obtriangular, eglandular-pilose to villous, or papillose-glandular, with few sessile oil globules; throat slightly oblique; teeth linear subulate shorter than to as long as calyx tube. Corolla blue, deep mauve or yellow (var. lutea Hook. f.), 12-15 mm; tube carved, somewhat exserted from calyx. Mature nutlets not seen, but immature brown, granular-tuberculate.