Herbs, rarely shrubs. Leaves opposite or alternate, simple and entire, exstipulate. Flowers hermaphrodite or unisexual, usually regular, generally arranged in spikes or cymes or clusters, each flower seated within 2 scarious bracteoles and subtended by a larger scarious bract. Perianth inferior, persistent, rigid and scarious, often coloured, of 4–5 free or slightly connate segments, imbricate in bud. Stamens hypogynous, 4–5, seldom fewer, opposite to the sepals; filaments free or connate, or united with intervening staminodia into a cup-shaped ring; anthers 1- or 2-celled. Ovary superior, 1-celled; style long or short, simple or divided into 2–3 branches or separate styles; ovules 1 or more, attached to a slender basal funicle. Fruit usually a membranous utricle, rarely a capsule or berry, enclosed or resting upon the persistent perianth. Seeds 1 or more, usually compressed, vertical; albumen farinaceous; embryo annular or curved.

A moderate order, comprising 48 genera and nearly 500 speeies, most plentiful in tropical or warm countries, absent in cold climates or on the tops of high mountains. Some species of Amarantus and Celosia (cockscomb) are often cultivated in gardens, but as a whole the order is composed of weedy unattractive plants possessing no useful properties. The only New Zealand genus is found in all warm countries.

1. Alternanthera, Forsk.

Annual or perennial herbs, usually prostrate or decumbent, rarely erect, glabrous or more or less pubescent or tomentose. Leaves opposite. Flowers small, whitish, capitate; heads sessile in the axils of the leaves, often clustered. Perianth 5-partite; segments unequal, the anterior and 2 posterior flattened, the 2 lateral innermost, concave. Stamens 2–5; filaments short, connate at the page 577base into a membranous cup, with or without intervening stami-nodia; anthers 1-celled. Ovary orbicular or obovoid; style short or almost wanting; stigma capitellate or rarely 2-fid; ovule solitary, pendulous from an elongated basal funicle. Utricle compressed, ovoid or orbicular or obcordate; margins often thickened or winged. Seed vertical, lenticular; testa coriaceous.

A small genus of 16 or 18 species, mainly tropical or subtropical, most abundant in America. The New Zealand species is a common weed in warm countries.

• 1. A. sessilis, R. Br. Prodr. 417.—A prostrate or decumbent herb. Stems numerous from the root, branched, creeping and rooting, sometimes ascending at the tips, 4–18 in. long, glabrous or with 2 opposite pubescent lines. Leaves variable in size,½–3 in. long, linear-lanceolate to linear-oblong or oblong-obovate, obtuse or acute, narrowed to the base, entire or obscurely denticulate, glabrous or pubescent in the axils. Flowers aggregated in dense axillary clusters ¼–⅓ in. diam. minute, whitish, about 1/12 in. long. Perianth-segments glabrous, rigid, acute. Stamens 2–3. Utricle broadly obcordate, with broad corky wings.—Hook. f. Fl. Nov. Zel. i. 212; Handb. N.Z. Fl. 234. A. denticulata, R. Br. Prodr. 417; A. Cunn. Precur. n. 367; Raoul, Choix, 43; Benth. Fl. Austral. v. 249.

  North Island: Marshy places from the North Cape southwards to Rotorua and Hawke's Bay, rare and local to the south of Auckland. Sea-level to 1000 ft.