Flora of New Zealand Series

alligator weed

Perennial herb; stems creeping or floating, ascending towards apex, rooting at the lower nodes, branched, hollow, with a longitudinal hairy groove on 2 opposite sides. Lvs subsessile or with petiole to 5 mm long, with a ring of white hairs between the 2 opposite lf bases. Lamina 3-13 × 1-3.5 cm, elliptic to oblanceolate or obovate, glabrous or slightly hairy near the attenuate base; apex obtuse or acute. Infls in upper axils, mostly 1-2 cm diam., capitate, white; peduncles to 9 cm long with 2 opposite longitudinal hairy grooves, occasionally heads shortly pedunculate and terminal. Bracts 2.5-3.5 mm long, ovate-acuminate; bracteoles similar to bracts, somewhat smaller, persistent. Tepals 5-7 mm long, oblong to ovate, acute or obtuse. Fertile stamens 5; staminodes = stamens. Style short, thick; stigma capitate. Fr. not seen.

N.: N. Auckland as far S. as Auckland City.

Brazil 1906

Drains, streams, swamps and similar wet places.

Alligator weed forms dense floating mats in stagnant or slow moving water, and also grows in dune hollows behind beaches west of Auckland. It has spread fairly rapidly since it was first recorded by Cheeseman at Aratapu on the N. Wairoa R. It has also been known in N.Z. as Telanthera philoxeroides.