Annual herb, 0.3- 1.4(2) m high. The roots are thin and brown. The stem is erect, round and hollow, with a diameter of 2-6 mm at the base and branches above the middle. The basal leaves withered at flowering stage; Cauline leaves are sessile or short-stalked, elliptic to ovate-lanceolate, 3.5-9 cm long and 1-4 cm wide, with long tapering apex, blunt base, 3-5 veins, arc-shaped, obviously protruding from the back, and leaflike uppermost leaf bud. Large conical cymes are loose, spreading, up to 50 cm long, with many flowers; Pedicel thick, erect or oblique, unequal in length, 6-40 mm long; 5 flowers, 2.5 cm in diameter; Calyx green, equal to corolla length 1/4- 1/2, lobes narrowly oblanceolate or narrowly elliptic, 3-6 mm long, apex acuminate or acute, base narrowed, edge with narrow white film, often rolled out, and back with 3-5 thin and inconspicuous veins; Corolla yellow, with many purple spots on the upper part, lobes oval or oblong, length 1- 1.5 cm, tapering or acute at the top, narrow at the base, and two large yellow-green and semicircular glandular points in the middle; Filaments linear, 5-6.5 mm long, anthers oblong, about 2.5 mm long; Ovary sessile, lanceolate, ca. 8 mm long, short style, small stigma, capitate, 2-lobed. Capsule sessile, narrowly ovoid, 2.3 cm long; The seeds are brown and round, with tumor-like protrusions on the surface. Chromosome 2n =18,24. The flowering and fruiting period is June-165438+1October.