An erect, perennial, several-stemmed herb up to 2.5 m. high; stems usually unbranched, more or less ribbed, scabrous to shortly hispid and with scattered spreading bristles 2–3 mm. long. Leaves sessile or subsessile, 6–12 x 1.0–1.8 cm., the superior ones progressively smaller, dense, narrowly lanceolate, hispid above and below or shaggy below, acute at apex, rounded to subcordate at base, almost leathery, with the secondary nerves not or hardly perceptible. Inflorescence a more or less dense terminal panicle with indumentum of short dense rigid hairs mixed with very numerous spreading yellowish bristles 2–3 mm. long. Bracts numerous, ovate to lanceolate, rounded to subcordate at base. Calyx densely bristly outside, sericeous inside with long ascending hairs; lobes narrowly triangular to narrowly lanceolate, 7–11 x 1.5–2.0 mm. when flower newly expanded, increasing to 15 mm. long in fruit. Corolla blue, violet or lilac; tube 6–7 mm. long, funnel-shaped, glabrous outside; lobes 12–20 x 2.5–4.0 mm., narrowly ovate-lanceolate with attenuate apices, more or less sericeous outside, mainly to the apex and with some appressed short hairs inside. Stamens inserted near the apex of the corolla tube; anthers 6–10 mm. long, minutely scabrous; terminal appendages 6–11 mm. long; filaments c. 2 mm. long with basal appendage densely hairy. Style 22–29 mm. long. Fruit usually of 1–2 well developed nutlets, the other ones abortive; nutlets c. 5 x 4 x 4 mm., ovoid, verrucose, keeled to the apex, rounded at back.
