Calyx 6.5–7 mm. long, clearly 10-nerved, subglabrous to finely retrorse pubescent especially on nerves; lobes 2.5–3 mm. long, shorter than tube, triangular, obtuse, coarsely hairy on margin.
Flowers in subcompact spike-like racemes at ends of branches, shortly pedicellate, solitary in axils of leaf-like bracts, inflorescence becoming lax at fruiting.
Erect annual herb, 10–50(250) cm. tall; stems slender, erect, simple or branched from about midway or above, hispid with retrorse hairs.
Corolla yellow with purplish venation, to c. 12 mm. long, narrow at base widening into limb of short, rounded, subequal lobes.
Bracts 5–18 x 2–3.75 mm., ovate, acute or obtuse, 1-nerved, leaf-like, entire or with 1 or 2 teeth towards apex.
Filaments all glabrous, anther thecae apiculate.
Bracteoles 3–5 x 0.5–1.75 mm., linear.
Capsule 5–6 x c. 3 mm., oblong-ovoid.
Pedicels 1–1.5 mm. long.