毒马草 du ma cao

Herbs annual. Stems ca. 20 cm tall, erect or ascending, spreading hirtellous. Petiole short to almost absent; leaf blade lanceolate to elliptic, 1-2 cm × ca. 5 mm, sparsely pilose, base cuneate, margin entire or remotely serrulate, apex acute. Verticillasters 6- to many flowered; bracts longer than flowers. Calyx 8-10 mm, tube cylindric, villous, l0-veined; teeth equal or subequal, oblong-lanceolate, 3-4 mm, apex spiny, ciliate; fruiting calyx slightly dilated, urceolate-campanulate, distinctly veined. Corolla yellow; tube included; upper lip oblate, ca. 1.5 mm, 2-lobed; lower lip ca. 1 mm. Nutlets gray-brown, triquetrous, ovoid, ca. 1.5 mm, smooth. Fl. and fr. Jun-Aug.

Valleys, thickets. Xinjiang [Russia, Turkmenistan; SW Asia, Europe].

A toxic weed.