Flora of New Zealand Series

Fls bisexual, in a terminal panicle which is soon pushed aside by a lfy shoot from the axil of an adjacent lf. Larger bracts foliaceous, us. 2 together, sts exceeding panicle; smaller bracts chaffy, 2 associated with each pedicel and fl. Fls articulate to pedicel, small, actinomorphic. Per.-tube short, becoming ± fleshy as fr. ripens; tepals subequal, patent, marcescent. Staminal filaments ± flattened but not greatly thickened, glab.; anthers dorsifixed and versatile. Ovary superior, sessile, globose; nectaries slit-like, one over upper part of each septum; ovules several to ∞ in each locule; stigma ± 3-lobed. Fr. baccate, becoming dry with age. Seeds us. curved, black. Tufted to arborescent; trunk woody with characteristic secondary thickening, the stout axis continued vertically downwards in an equally stout rhizome (sts 2). Lvs long-lived, crowded in tuffs (to 200 or more) at ends of branches, long-linear to narrow-elliptic, ± petiolate, the strong fibrous veins narrowly oblique to midrib. About 15 spp. scattered from India to Queensland and the Pacific, recorded also in S. America. The 5 N.Z. spp. endemic. Cordyline Comm. ex Juss.  nom. cons.  : type sp., C. terminalis (L.) Kunth.

Universally called "cabbage trees"; the Maori generic name is Ti.

The widely distributed C. terminalis, previously recorded from old plantations, is considered to be wholly adventive, both in northern New Zealand and in the Kermadec Is. It and related spp. differ from N.Z. spp. in having outer tepals shorter than inner, stamens as tall as inner tepals, and terminal papillose, not trilobed, stigma.

In the infl. bracts occur not singly but 2 (occ. more) together, with only a short internode between. At the base of each fl. the raceme axis bears a ± ovate bract subtending the much reduced floral branchlet, and ± enclosing an opposed 2-nerved prophyll bract that is borne wholly on the very short lateral axis. Beyond this is the pedicel proper (us. extremely short) which is articulated to the base of the corolla. In each sp. the 2-nerved bract tends to have a characteristic shape. The large foliaceous bracts of the main panicle axis show at least one fairly reliable interspecific character. As pointed out by Esler (Bull. Wellington bot. Soc. No. 32, 1961, 10–11) in C. banksii at each node there are 2–3 minor branches, as well as one major one, these minor branches each associated with one of the minor bracts. Such minor branches are rarely seen in C. australis, but occur in C. pumilio.

Lvs are mostly smooth-margined but in several if not all spp. lvs of seedlings may be finely scabrid.

The bulky descending rhizomes anchor the plants very firmly to a depth of a metre or more, and also store starch. Aerial rhizomes, also strictly positively geotropic, often arise, especially on ± horizontal branches (e.g. Moar, Bull. Wellington bot. Soc. No. 26, 1953, 29, fig.; Cockayne, T.N.Z.I. 41, 1909, 405–406).

Morice (J. Sci. Food Agric. 13, 1962, 666–669) records analyses of seeds of all 5 N.Z. spp. of Cordyline, the oil content ranging from 22.3% of dry weight of seed in C. kaspar to 36.9% in C. australis. In all spp. linoleic acid forms a high proportion (c. 80–90% by weight) of the total fatty acids, but C. banksii and C. kaspar have more oleic acid than the others. The same author ( N.Z. J. Sci. 8, 1965, 446–449) has estimated how much an acre of C. australis could yield annually of linoleic acid, an acid that is used industrially and is essential for the growth of humans as well as animals.