Page:Manual of the New Zealand Flora.djvu/790

750 long. Perianth-segments rhombic-orbicular. Fruit small, about $1⁄10$ in. long, broadly ovoid, slightly compressed, keeled on the back, beak short.—A. Bennett, l.c. xxv. (1887) 177; ''Cheesem. in Trans. N.Z. Inst.'' xvi. (1884) 410. P. heterophyllus, ''Hook. f. Handh. N.Z. Fl. 279, 742 (not of Schreber)''. P. natans var. australis, ''Kirk ex A. Bennett in Journ. Bot.'' xxv. (1887) 177.

4. P. ochreatus, Raoul, Choix, 13, t. 7.—Stems slender, striate, branched, long or short according to the depth of the water. Leaves all submerged, alternate or the upper opposite, sessile, 1–4 in. long, ⅛–¼ in. broad, linear-ligulate, obtuse or emarginate at the tip, membranous, 3- or 5-nerved with or without iiner parallel veins between, transverse veins few; stipules free, at length conspicuously lacerate. Peduncles stout, erect, usually shorter than the leaves, 1–3 in. long; spike short, oblong, about ½ in. long. Fruit broadly obliquely ovoid, subcompressed, $1⁄10$ in. long, back rounded, beak short, thick.—''Hook. f. Fl. Nov. Zel.'' i. 236, and ii. 336; ''A. Bennett in Journ. Bot.'' xxv. (1887) 178. P. gramineus, ''Hook. f. Handb. N.Z. Fl. 279 (not of Linn.)''. P. obtusifolius, ''Benth. Fl. Austral.'' vii. 172 (not of Mert. and Koch).

5. P. pectinatus, ''Linn. Sp. Plant.'' 127.—Stems long, filiform, much branched, often forming dense masses. Leaves all submerged, alternate, sheathing at the base, 2–4 in. long by $1⁄20$–$1⁄15$ in. broad, very narrow-linear or almost filiform, upper channelled on both surfaces, lower flatter, 1–3-nerved with transverse veinlets; stipules adnate with the sheathing base of the leaf. Peduncles long, slender, filiform, not thickened upwards; spike 1½–2 in. long, of distant whorls of flowers. Fruit rather large for the size of the plane, about ⅛ in, long, turgid, obscurely keeled on the back, slightly convex in front, rugose when dry, beak very short.—''Hook. f. Fl. Nov. Zel.'' ii. 386; ''Handb. N.Z. Fl. 279; Benth. Fl. Austral.'' vii. 173; ''A. Bennett, Journ. Bot.'' xxv. (1887) 178.