Flora of New Zealand Series

Indian knotweed

Large rhizomatous or stoloniferous perennial herb forming thickets; roots rather slender; stems erect, thick, sometimes reddish, glabrous, to c. 1.5 m tall, the lower nodes with small tubercles. Lvs on stems and branches similar; petioles 1-4 cm long, red. Lamina 8-30 × 2.5-9 cm (infl. lvs sometimes smaller), oblong-lanceolate; midrib red, glabrous; lateral veins in c. 20 pairs, pink and puberulent beneath; margin ciliolate, entire or sinuate; base cordate to rounded; apex long-acuminate. Ochreae to c. 7 cm long, glabrous, soon papery brown, truncate. Panicles large and diffuse with slender branches; axes acutely angular, puberulent or glabrate, red; pedicels short, often hidden by the membranous brown bracts and bracteoles. Perianth 2.5-4 mm long, white; segments obovate to broad-oblong, eglandular, imbricate, probably accrescent. Fr. not seen.

N.: Auckland, southern Manawatu, Wellintgon; S.: Nelson Province, Westland, Queenstown, Dunedin and Invercargill areas, absent from the drier eastern side; St.: Halfmoon Bay.

Temperate Himalaya 1958

Roadsides and waste land near settlements, a cultivation escape well-established in a number of localities.

FL Nov-May.

Indian knotweed is a distinctive sp. in N.Z. and presumably increases vegetatively. The white fls have conspicuous purple anthers.