Description from Flora of China
Herbs perennial, rhizomatous. Leaves sagittate, base strongly cordate, stellate hairy abaxially, margin coarsely crenate. Verticillasters in oblong spikes. Calyx tubular, conspicuously 10-veined; teeth 5, equal, subulate, apex spinescent. Corolla violet, 2-lipped; tube pilose annulate at middle, throat tomentose; upper lip erect, equal to or shorter than lower lip; lower lip 3-lobed; middle lobe broadly reniform, margin unequally denticulate or undulate; lateral lobes ovate-oblong, much shorter than middle lobe. Stamens 4, included; filaments densely tufted hairy, unequally papillate near base, triangular-dilated at base; anthers reniform. Style longer than stamens, apex unequally 2-cleft, lobes linear-oblong.
Monotypic: China, Kyrgyzstan.
The genus name is based on Metastachys Knorring (1959), an illegitimate later homonym of Metastachys van Tieghem (1895). Airy Shaw drew attention to the status of Knorring's
name and suggested, but did not validate, Metastachydium as a replacement. Wu and Li (Acta Phytotax. Sin. 13: 73. 1975) took up Airy Shaw's name but did not give the correct page
number for Knorring's protologue and thus the genus name and their new combination within it must date from their 1977 account in which the full reference is given.