Herb 50-60 cm high. Stems square and ribbed; nodes dark red. Leaves with lamina veins raised below and ± sunken above. Inflor. (except lower part of rachis) scarlet. Calyx 2-2.5 cm long, ribbed, 2-lipped. Corolla 3-4 cm long to apex of straight upper lip; lower lip c. 5 mm long (middle lobe) and cup-shaped; lateral lobes shorter reflexing. Style long exserted, red. A typical strain.