Rooted herbaceous hygrophyte 1-2 m tall, with a horizontal rhizome, forming coloÂnies. Stems long, sympodial, 1-leaved, leaves erect, exserted, with short petiole forming dilated sheath at base; lamina cordate (in typical variety) to ovate or 'lanceolate' (in var. ovalis), c. 230 x 70 mm, firm, smooth. Flowering stem emerging from sheathing base of leaf and about as long; peduncle short, puÂbescent, enveloped by large sheathing bract. Spike cylindrical, up to c. 100 mm long and 20 mm broad, flowers dense, clustered, blue, rarely white. Perianth c. 15 mm long, shortly pubescent on outside, funnel-shaped, upper fin broader than side-lobes, with vellow blotch in centre. Stamens unequal, upper shorter, included, lower exserted, filaments filiform, pubescent. Ovary: abortive carpels surviving as ridges on walls of ovary; style long or short, slender; stigma apical. Utricle enveloped by accrescent base of perianth. Fig. 20.
