Branches angular or somewhat winged.
Sprawling to erect herb (low shrub), up to c. 60 cm high, sparingly to densely branched often from near the base, aromatic, densely covered with viscid-glandular hairs.
Flowers ± erect; pedicels 1–6 cm long, slender, elongating in fruit, hairy.
Leaves shortly petiolate; lamina membranous, 2–5 × 0.6–3.5 cm, elliptic or ovate to lanceolate, spathulate or obovate, base cuneate, apex acute to obtuse, sometimes sub-acuminate, entire or somewhat repand, glandular hairy at least along the margins and to a varying extent on the surfaces.
Corolla deep purple (or pink to violet coloured), veined, 3.5–5 cm long, infundibuliform, single or elsewhere sometimes double; tube up to twice as long as the calyx, rather narrow, villous or hirsute outside, glabrous inside; limb 1.5–2 cm long, 3–4.5 cm across, hairy on the nerves outside; lobes ovate or rotund, rounded to sub-acute.
Calyx 10–18 mm long, hairy all over; laciniae unequal, 8–15 × 1.5–3 mm, linear to spathulate, acute to obtuse, more densely hairy at the margins, erect or ± spreading; in fruit somewhat enlarged.
Disk yellowish, 0.8 mm high, laterally sulcate, crenate-repand.
Stamens subequal, one shorter and 2 slightly longer; filaments 1.3–1.6 cm long, attached about one-third down the corolla tube, geniculate just above the insertion; anthers bluish, c. 1.5 mm long, deeply cordate.
Ovary 3 × 1.5 mm, elongate-conic or subpyramidal, glabrous; style 2–2.3 cm long, somewhat geniculate at the top.
Fruit stramineous, c. 10 mm long, with the foveolate placenta persistent after seeds have fallen.