Style (0.3–)0.5–3 mm. long in fruit.
Fruit often reddish, 6–9 mm. wide; nutlets compressed ovoid, (2.5–)3.5–4 mm. long, 3–3.5 mm. wide, covered all over with fairly short usually slender glochidia 0.5–1 mm. long and with few short additional tubercles above or with upper face almost or quite devoid of tubercles save for a median line, occasionally with peripheral ones joined at base to form a ± distinct margin but not as marked as in many species of the genus; there are, however, numerous intermediate fruit patterns.
Flowers in terminal and axillary, simple, dichasial or trifid cymes but not forming densely branched inflorescences; individual cymes short at first but soon 10–25 cm. long; pedicels mostly short, 2–7(–12) mm. long or that of central flower of dichasium up to 1.5 cm.; axes sparsely to densely adpressed pubescent.
Calyx-lobes narrowly ovate to oblong or elliptic-obovate, 1.2–1.5(–3.5) mm. long, 0.4–1.2(–2) mm. wide, enlarging in fruit, 3–4 × 1.5–1.8 mm., acute to ± rounded at the apex, pubescent and ciliate and sometimes with marked cystolith-tubercles.
Perennial or less often annual or biennial herb (15–)25–120 cm. tall; stems rough with ± adpressed upwardly directed hairs above but spreading or deflexed beneath, very dense on young parts; usually with a thick woody tap-root.
Radical leaves narrowly ovate, elliptic-oblong, linear-oblong or oblanceolate, 8–21 (–30) cm. long, 1.1–6 cm. wide, subacute at the apex, long-attenuate at the base, rough with rather sparse to dense short adpressed white hairs from conspicuous white cystolith dots, less densely placed on the undersurface; petiole 2–10 cm. long, spreading pubescent; cauline leaves similar, linear-lanceolate to ovate, 1.5–17(–30) cm. long, 0.2–5 cm. wide, subacute to acute at the apex, contracted to or slightly widened at the base, sessile or pseudopetiolate.
Corolla blue or pinkish mauve turning bluish, sometimes with yellowish white centre or less often white or white with blue or pink centre; tube 1.5–2(–2.5) mm. long; lobes rounded-oblong, (1.2–)1.5–3 mm. long, 1–3 mm. wide.
Inferior cauline leaves long-petiolate, up to 25 x 3(5) cm., linear-lanceolate to linear-oblanceolate, sometimes narrowly lanceolate, with a petiolar portion up to 7 cm. long (radical leaves not seen).
Cauline leaves at middle stem up to 14.0 x 1.5 cm., narrowly lanceolate to linear-lanceolate, hispid-pilose on both surfaces, acute at apex, acute to obtuse at base; midrib and nerves depressed above, prominent below.
Cymes usually grouped by two on each peduncle, often with a flower at the fork and arranged in an ample lax panicle.
Pedicels c. 2 mm. long, elongating up to 7 mm. and much recurved in fruit.
Calyx c. 2 mm. long, shortly hispid outside, ciliate at the margins, devided to near the base; lobes ovate to oblong-elliptic, subacute to rounded at apex, accrescent.
Corolla glabrous, blue; tube 1.5–2.0 mm. long; lobes 1.0–1.5 x 1.0–1.5 mm., circular to oblong, rounded at apex, spreading; fornices c. 0.4 x 0.6 mm., slightly bilobed, papillose.
Stamens inserted about the middle of the corolla tube; anthers c. 0.5 mm. long, elliptic; filaments about as long as the anthers.
Style c. 0.5 mm long; stigma subcapitate.
An erect or ascending perennial herb up to 1.2 m. high; stem (or stems) much branched, clothed with somewhat rigid hairs, spreading or retrorse on the lower part, appressed to the upper part as on the branches.