15–40 cm (6–16 in.). Stem roundish–bristly, rough-haired, upper part usually branched.
Corolla wheel-shaped–campanulate (bell-shaped), slightly zygomorphic, 4–6 mm wide, light blue, fused, 5-lobed. Calyx-tube same length as calyx, curved, large white protuberances in throat. Calyx 5-lobed from base, densely hairy. Calyx lobes tapered, sharp-tipped. Stamens 5. Gynoecium fused, single-styled. Inflorescence initially dense, later extending into a 1-branched scorpioid cyme, all flowers with subtending bracts.
Alternate. Basal leaves stalked, stalks winged, stem leaves stalkless, widely attached. Blade elongated–lanceolate–ovate, shallowly toothed, with crinkled margins, both sides hairy.