Page:Manual of the New Zealand Flora.djvu/389

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Siegesbeckia.]
COMPOSITÆ.
349

Kermadec Islands, North Island: In various localities as far south as the East Cape, but not common; usually near the coast. Punawaru. January–March.

This was treated as a naturalised planb by Hooker, but as it was collected by Banks and Solander during Cook's first voyage its nativity is unquestionable.


15. BIDENS, Tourn.

Annual or perennial usually erect herbs. Leaves opposite, toothed or incised or pinnately divided. Heads corymbosely panicled or subsolitary, on long peduncles, heterogamous and radiate, or homogamous and discoid. Involucre campanulate or hemispherical; bracts in about 2 series, connate at the base, the outer herbaceous, the inner membranous. Receptacle flat or convex, paleaceous. Ray-florets when present female or neuter; ligule white or yellow, spreading. Disc-florets hermaphrodite, tubular, 5-toothed. Anthers usually obtuse at the base. Style-branches of the hermaphrodite florets hairy above, with a long or short subulate point. Achene broad and compressed or slender and tetragonous, often narrowed at the tip. Pappus of 2–4 rigid retrorsely hispid bristles.

A large genus of over 100 species, widely spread in tropical regions, but most plentiful in America. The single New Zealand species is a common weed in all warm countries and many temperate ones.


1. B. pilosa, Linn. Sp. Plant. 832.—An erect glabrous or pubescent herb 1–3 ft. high; branches angular, grooved. Leaves very variable, simple or pinnate; segments 3 or 5, stalked, ¾–2 in. long, ovate or ovate-lanceolate, acute or acuminate, serrate or rarely lobed, thin and membranous. Heads few, terminal on long slender peduncles, yellow, ⅓–½ in. diam.; involucral bracts about ¼ in. long. Ray-florets few and short, often entirely wanting. Achenes black, slender, 4-angled, striate, crowned with 2 or 4 barbed awns.—A. Rich. Fl. Nouv. Zel. 235; A. Cunn. Precur. n. 442; Raoul, Choix, 45; Hook. f. Handb. N.Z. Fl. 138; Benth. Fl. Austral. iii. 543; Kirk, Students' Fl. 318. B. aurantiacus. Col. in Trans. N.Z. Inst. xxvii. (1895) 388.

Kermadec Islands, North Island: Not uncommon as far south as the East Cape. November–March.


16. COTULA, Tourn.

Creeping or tufted perennial or annual herbs, usually of small size, often aromatic. Leaves alternate, pinnatifid or pinnatisect, rarely entire or toothed. Heads small, peduncled, heterogamous and discoid or rarely homogamous through the suppression of the female florets, sometimes diœcious. Involucre hemispheric or campanulate; bracts in about 2 series, membranous or herbaceous; margins often scarious. Receptacle flat or convex or conical,