Flora of New Zealand Series

Type locality: "Baie des îles". Type: P(?).

Rhizome short with close fibrous stipules and roots. Branches erect, at first simple with long lvs, ∞ short lfy branchlets produced in lf-axils in spring and elongating in autumn, sts rooting from nodes. Stipules to 2 cm. long, free, open, obtuse, with many close nerves that persist as fibres at older nodes. Lvs all submersed, sessile; lamina 1.5–10 cm. × 2–5 mm., entire, linear-oblong, obtuse to slightly emarginate, only slightly narrowed to base, membr., longitudinal nerves ∞, fine and close, one in each half us. stronger. Peduncles from axils of upper lvs, 2–4 cm. long, simple, slender. Spike to 1.5 cm. long, dense. Achene c. 3 × 2.5 mm., flattened on sides, keel ± 3-ridged, beak rather well-developed, curved.

DIST.: N., S., A. (Adams Id, E. J. Godley).

Also recorded from Australia and E. Asia.

In open, sts slow-moving waters.

FL. 11–2–(4). FT. 12–3–(4).

Quite distinct from the other indigenous spp. The only naturalized sp., P. crispus, has lvs somewhat similar in size and shape but differing in ± crisped and minutely serrate margins and in the 3 conspicuous, widely spaced nerves.