Plants 3–20(–30) dm. Stems striate, often striped or suffused with red or pink, branched distally, hollow. Leaves: ocrea brown, loosely funnelform, 2–4 cm, margins strongly oblique, glabrous or puberulent with flattened, whitish hairs along veins; petioles of basal leaves pinkish green or reddish green, ca. equaling or longer than blade, thick, fleshy, those of cauline leaves absent distally; basal leaf blades palmately veined with 5–7 basal veins, 30–45(–60) × 10–30 cm, veins pubescent primarily along veins with flattened, whitish hairs. Inflorescences 250–500-flowered, 15–40 cm; peduncle 1–8 cm, glabrous. Pedicels articulated at or proximal to middle, 2–5 mm, glabrous. Flowers: tepals oblong-ovate, 2.3–4 × 1–2.5 mm, margins hyaline, apex obtuse. Achenes 6–10(–12) × 6–11 mm including wings, 4–8 times longer than perianth; wings tan, veined, 3–4 mm wide, membranous. 2n = 44.
