Description from Flora of China
Leptostachia Adanson (1763), not Leptostachya Nees (1832, nom. cons. prop.).
Herbs, perennial, erect. Stems 4-angular. Stipules absent. Leaves simple, opposite; leaf blade margin serrate. Inflorescences a terminal [or axillary] spike. Flowers perfect, each with a bract and a bracteole. Calyx connate, tubular, 5-ribbed; limb 2-lipped; abaxial lip with 2 short triangular lobes; adaxial lip with 3 apically ± hooked long subulate lobes. Corolla connate, tubular-funnelform; limb 2-lipped; abaxial lip larger, patent, with 3 imbricate lobes; adaxial lip erect, margin subentire but apically emarginate or shallowly 2-lobed. Stamens 4, inserted in corolla tube, anterior 2 longer; filaments filiform; anthers dorsifixed, cells parallel, not convergent at apex, longitudinally dehiscent. Gynoecium pseudomonomerous (2-carpellate with 1 carpel reduced developmentally); ovary superior, 1-locular, with basal placentation and 1 orthotropous ovule; style single, apical, elongate; stigma 2-lipped. Fruit an achene, enveloped in persistent calyx, 1-seeded. Seeds with an oblong embryo; endosperm thin, with 2 layers of cells.
One species: E and S Asia, E North America.