Ruyschiana spicata Miller; Zornia linearifolia Moench.

Stems erect, minutely retrorse hairy, sparsely hairy toward base. Leaves sessile or subsessile, linear to lanceolate-linear, 3.4-6.2 cm, sparsely minutely hairy on veins, glabrescent, base narrowly cuneate, apex obtuse. Verticillasters in apical 4-6 nodes, ± crowded; bracts ovate-elliptic, to 1/2 as long as calyx, apex acute, densely ciliate. Calyx 1-1.2 cm, densely pubescent basally, sparsely pubescent at apex, 2-lipped to ca. 2/5 its length; upper lip teeth divisions to 2/3 of lip, middle tooth ovate-elliptic, slightly wider than lateral teeth, lateral teeth triangular to broadly lanceolate; lower lip purplish, with 2 lanceolate, apically acute teeth, margin ciliolate. Corolla blue-purple, 1.7-2.4 cm, pubescent outside. Fl. Jul.

Source of an essential oil.

Montane grasslands, stony areas in grasslands. Heilongjiang, Nei Mongol, Xinjiang [Kazakhstan, Kyrgyzstan, Mongolia, Russia, Turkmenistan; Europe]