Thalia canniformis G. Forster, Fl. Ins. Austr. 1. 1780; Actoplanes canniformis (G. Forster) K. Schumann; Donax arundastrum Loureiro.

Herbs 1.5--4(--5) m tall. Stems with basal, canelike internode 1--2.5 m. Leaf sheath to 15 cm; petiole 8--20 cm, thickened into a cylindric pulvinus; leaf blade broadly ovate to elliptic, 10--25 × 10--45 cm, abaxially villous along midvein, base rounded to obtuse, apex acuminate. Inflorescences often branched at base, to 20 cm, slender; bracts 9--11, green, obovate to lanceolate, 2.5--3.5 cm, deciduous after anthesis. Pedicel thickened in fruit. Sepals white, triangular-ovate, 3--3.5 mm, glabrous. Corolla tube 8--10 mm; lobes linear, 1--1.4 cm × 2--3 mm. Outer staminodes white, obovate, 1.2--1.4 cm × 5--6 mm; callose staminode yellowish, ca. 1.5 cm, apex usually emarginate; cucullate staminode light yellow at apex. Fertile stamen ca. 8 mm, with a narrowly triangular appendage. Ovary sericeous. Fruit white to pale cream, 1--1.5 cm in diam., dry, indehiscent. Seeds 1 or 2, brown, globose to complanate. Fl. Jun.

Rather wet places in secondary forests and dry bamboo scrub. Taiwan (Lan Yu opposite SE coast) [Cambodia, India, Indonesia, Malaysia, Philippines, Thailand, Vietnam].