Stachys nigricans Benth.

Perennial, erect, single-to few-stemmed herb, 0.4-1.2 m tall, with several horizontal fusiform roots; stems simple or sparingly branched above, villous to hispid with longish, spreading to antrorse multicellular hairs and with an interpetiolar ridge at the nodes. Leaves sessile or subsessile, drying dark brown to blackish; blade oblong-lanceolate to linear-lanceolate, 30-60 x 3-10 mm, strigose with usually bulbous-based appressed hairs, apex obtuse, base truncate to subcordate, margin crenate, slightly thickened. Inflorescence simple or occasionally with a pair of branches near the base, lax below, denser above; verticils usually 6-flowered; lower bracts leaf-like, becoming differentiated and equal to or shorter than the calyx above. Calyx fairly densely appressed-hispid, 5-6 mm long. Corolla usually white, occasionally speckled, or tinged with pink or mauve; tube 6-7 mm long; upper lip ascending, subrotund, concave, 3 mm long; lower lip deflexed, 6-7 mm long.