Common in most warm countries, and possibly only naturalised in New Zealand. It is very closely allied to the equally abundant K. monocephala, to which I formerly referred it, but which can be distinguished by the glume of the fertile flower having the upper part of the keel winged or crested and more or less glandular.
2. CYPERUS, Linn.
Annual or more commonly perennial herbs. Stems erect, simple below the inflorescence. Leaves at the base of the stem, usually long, the lowest sometimes reduced to sheaths. Inflorescence umbellate or capitate, often large and compound; bracts at the base long, leaf-like, spreading. Spikelets oblong or linear, compressed; rhachilla persistent. Glumes usually many, distichous; the two lowest empty; four at least and generally many of the succeeding ones hermaphrodite and fruit-bearing, falling away from the rhachilla one by one, commencing with the lowest; the uppermost 1–3 sterile or empty. Stamens 2–3, rarely 1. Style continuous with the ovary, not thickened at the base; branches 3, filiform. Nut triquetrous or plano-convex, the flat face against the rhachilla, surface smooth.
A large genus of over 300 species, most abundant in the tropical and subtropical districts of both hemispheres, comparatively rare in temperate regions. The two New Zealand species are widely distributed; one of them is certainly a recent introduction, and possibly the other as well.
| Small, 1–3 in. high. Inflorescence of a single head; spikelets 1–3 | 1. C. tenellus. |
| Tall, 1–2 ft. high. Inflorescence in a compound umbel; spikelets very numerous | 2. C. vegetus. |
The tropical C. rotundus, Linn., easily recognised by the black ovoid tubers on the creeping stolons, and hence frequently known by the name of "nutgrass," has become naturalised in the vicinity of Auckland. It is a most pernicious weed.
1. C. tenellus, Linn. f. Suppl. 103.—A small densely tufted annual. Stems numerous, very slender, almost filiform, 1–3 in, high. Leaves few, much shorter than the stem, filiform. Spikelets 1–3 together, digitate, much flattened, oblong, obtuse, large for the size of the plant, ⅙–¼ in. long; bracts 2, setaceous, one erect and continuous with the stem, the other much smaller. Glumes 10–25, regularly distichous, ovate, obtuse or mucronate, boatshaped, conspicuously 5–9-nerved, varying in colour from almost white to red-brown. Stamens 1 or 2. Style-branches 3, linear. Nut rather more than half the length of the glume, elliptical, acutely trigonous, smooth.—Hook. f. Handb. N.Z. Fl. 745; Benth. Fl. Austral. vii. 265; C. B. Clarke in Fl. Cap. vii. 164.
North Island: From the North Cape southwards to Taranaki and Hawke's Bay, abundant. Sea-level to 1500 ft. November–December.
A common South African plant, doubtfully indigenous in temperate Australia and New Zealand.
