Herbs, perennial, 30--70(--100) cm tall. Taproot stout, dark purplish brown. Caudex thickened, with 1--3 heads, densely covered by persistent petiole bases. Leaves basal, wide, hard, persistent to anthesis; petiole distinct; leaf blade oblong-obovate, elliptic, or ovate, (5--)10--30(--40) X 3--8(--10) cm including petiole, base attenuate, apex usually obtuse to rounded. Inflorescences usually solitary, large, corymbiform or paniculate; main axis cylindrical, polished; rachis 3 or 4 X branched; branchlets slender and erect; sterile branches usually absent or simple and solitary on forks; spikes with 2--7 spikelets, densely clustered on upper part of branchlets; spikelets 1-or 2(or 3)-flowered; bracts broadly ovate, 1--1.5 mm, margin narrowly membranous; first bractlet 2--2.5 mm, margin membranous. Calyx obconical; tube basally and adaxially pubescent along ribs; limb pale purple or white. Corolla blue-purple. Fl. Jul-Sep, fr. Aug-Sep. 2n = 18.
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