块根荆芥 kuai gen jing jie

Plants perennial, with succulent walnut-sized tubers. Stems numerous, diffuse or ascending 15-45 cm tall, puberulent basally, slightly viscid, unbranched or branched. Petiole ca. 1/2 as long as blade; leaf blade broadly ovate to ovate-cordate, 1.2-2.5 × 1.2-2.5 cm, hirtellous, base truncate, margin serrate-crenate, apex somewhat obtuse. Verticillasters in ovoid, ± interrupted spikes less than 2.5 cm; bracts ovate to lanceolate, as long as calyx. Calyx ca. 4 mm; teeth subulate, ciliate, shorter than tube. Corolla purple blue; tube slender, ca. 2 × as long as calyx. Fl. Jun-Jul.

Thickets along streams; 4100 m. Xizang [Afghanistan, India]

Of uncertain affinity but easily recognized by the prominent tubers if they are present.