Gratiola hyssopoides Linnaeus, Mant. Pl. 174. 1771; Bonnaya hyssopoides (Linnaeus) Bentham; Ilysanthes hyssopoides (Linnaeus) Bentham.

Herbs, to 30 cm tall. Roots fibrous, tufted. Stems erect or somewhat ascending, simple, striate, glabrous. Leaves sessile, subamplexicaul, narrowly ovate to ovate-lanceolate, 5-15 X ca. 4 mm, glabrous, margin entire or with 2 or 3 pairs of inconspicuous small teeth; veins 3, parallel. Flowers in axils of upper leaves, solitary. Pedicel 0.5-3 cm, slender, ascending in flower, spreading to reflexed after flowering. Calyx ca. 3 mm, lobed to base; lobes lanceolate. Corolla red, purple, or white, with 2 convex lines at throat, 0.9-1.1 cm; lower lip 3-lobed, lobes subequal; upper lip deeply 2-lobed, lobes narrowly triangular-ovate. Fertile stamens 2, posterior. Staminodes 2, anterior; filaments short, divided. Style short, apex 2-lamellate. Capsule narrowly ovoid, ca. 6 mm. Seeds yellow-brown, oblong, obscurely ribbed. Fl. May-Oct, fr. Aug-Nov.

Dry fields, wet areas; ca. 1200 m. Guangxi, Hainan, Yunnan [India, Indonesia, Sri Lanka, Vietnam].