Much too closely allied to U. riparia, from which it can only be separated by the smaller size, usually shorter spike, and by the glumes being often tinged with chestnut-brown or purplish-red, whereas they are usually green in the forms of U. riparia. From U. filiformis it is removed by the stouter habit, broader flat leaves, and rather stouter spike.
12. U. filiformis, Boott in Hook. f. Fl. Nov. Zel. i. 286.—Culms densely tufted, extremely slender, filiform, 3–9 in. high, leafy towards the base. Leaves usually much exceeding the culms, very slender, filiform, 150–130 in. broad; margins involute, scabrid. Spike ½–1½ in. long, extremely slender, linear, lax, 115–110 in. broad; bract filiform, exceeding the spike. Glumes oblong-lanceolate, acute or acuminate, membranous, pale, equalling the utricles or nearly so. Utricles ⅛–⅙ in. long, lanceolate, acuminate, smooth and glabrous, faintly nerved; bristle twice as long as the utricle.—Hook. f. Handb. N.Z. Fl. 310; C. B. Clarke in Journ. Linn. Soc. xx. 391. U. debilior, F. Muell. Fragm. Phyt. Austral. viii. 151; Benth. Fl. Austral. vii. 435.
North Island: Auckland—Pirongia Mountain, T.F.C. Hawke's Bay—Ruahine Mountains, Colenso! H. Hill! Petrie! Taranaki—Mount Egmont, Petrie! Wellington—Tararua Mountains, H. H. Travers! T. P. Arnold! South Island, Stewart Island: In hilly and mountain districts throughout, but not common. 1000–4500 ft. December–January.
In its usual state this can be recognised without much difficulty by its small size and very slender habit, filiform convolute leaves, small slender spikes, and small narrow utricles, which only slightly exceed the glumes. But large forms are indistinguishable from states of U. riparia, U. cæspitosa, and others. Mr. C. B. Clarke refers to it the U. debilior, F. Muell., from Lord Howe Island.
14. CAREX, Linn.
Perennial herbs. Culms erect, more or less trigonous or rarely terete, often scabrid on the angles. Leaves mostly radical, grass-like, usually scabrid on the margins and keel. Spikelets unisexual or bisexual, rarely diœcious, solitary or more commonly arranged in clusters or spikes, racemes or panicles, all androgynous or the upper male with rarely a few female flowers at the top or base, the lower female often with a few male flowers at the base or top. Glumes imbricate all round the axis. Male flowers of 3 stamens, without perianth or hypogynous bristles. Female flowers consisting of a compressed or trigonous ovary, included in a flask-shaped or urceolate 2-toothed organ called the utricle or perigynium; style-branches 2 or 3, long, filiform, protruding beyond the utricle. Nut lenticular or plano-convex or trigonous, enclosed in the persistent more or less enlarged utricle.
An immense genus of probably over 1200 species, of worldwide distribution, but most abundant in temperate regions, rare in the tropics, save on high mountains. Of the 53 species found in New Zealand, no less than 37 are endemic, the remaining 16 being mostly widely spread. In elaborating the New Zealand species for this work I have received great assistance from the two chief authorities on the genus—Mr. C. B. Clarke, F.R.S., of Kew, and Pastor Georg Kukenthal, of Grub, near Coburg. My warmest thanks are due to both.
