Flora of New Zealand Series

Fls unisexual, in a terminal "spike". Infl. us. complex with 1 pseudanthium or several within each of 2 or more glume-like floral bracts. Each pseudanthium of 1, 2 or 0 ♂ and 1– ∞ or 0, often connate ♀. Upper bractlets subtending fls, hyaline or 0. Tepals 0. ♂ a single stamen, filament thread-like, anther 1-celled, versatile, opening lengthwise by a slit, rarely 2-celled and basifixed. ♀ a single unilocular ovary, fls free or often 2 or more ± connate, collateral or superposed in 1–2 series. Styles 1–(3–10) to each fl., occ. styles from all fls connate at the base. Ovule solitary and pend. Fr. with membr. pericarp dehiscing longitudinally, (ind. in Hydatella). Seeds with cop. endosperm. Small, tufted, grasslike and annual, or mosslike and perennial herbs. Stems slender, densely packed in perennial spp. Lvs linear or setaceous, in annual spp. all crowded at base of stem, in perennial spp. imbricate and crowded along the stems. A small family of c. 5 genera and c. 40 spp. mainly in Australia and N.Z., a few in Malaysia, Southeast Asia and South America.

There are two different interpretations of the fl. and infl. The first is that of the original monographer of the family G. Hieronymus (Abh. naturforsch. Ges. Halle 12, 1873, 115–222, and Engl. Bot. Jb. 7, 1886, 319–30). Hieronymus thought that Centrolepis and Gaimardia possessed bisexual fls composed of 1–(2) stamens and a gynoecium of 2–∞ single carpels, ± fused and superimposed. Hieronymus's interpretation was followed by Bentham and Hooker and subsequent authors.

Eichler, however, in Bluethdiagr. 1, 1875, 131 considered that the so-called "bisexual flowers" of Centrolepis and Gaimardia are most probably reduced infls or "pseudanthia", cymose structures consisting of 1–(2) male fls and 2–∞ female fls, all fls being reduced to respectively 1 stamen or 1 carpel. Hamann (Ber. dtsch bot. Ges. 75, 1962, 153–71) supports Eichler's interpretation to a large extent. The following descriptions have been drawn up on the basis of Eichler's and Hamann's hypothesis. The "flowers" described in Cheeseman's Man. N.Z. Fl. are here treated as "pseudanthia" and the stamens and carpels of Cheeseman as male or female fls.

Hieronymus and Eichler agreed as to the arrangement of the "flowers" or pseudanthia in the whole infl. They considered the whole infl. to be a spike or head, in which the "flowers" (Hieronymus) or pseudanthia (Eichler) are arranged in cymose partial infls or scorpioid cymes.

Fig. 16. CENTROLEPIDACEAE. Centrolepis ciliata : leaf, × 5; pseudanthium showing hyaline bract inside glume-like outer bract, superposed female flowers and part of filament of male flower; inflorescence, × 7½. Gaimardia setacea : leaf, × 5; pseudanthium showing glume-like bract, collateral female flowers and male flowers; inflorescence, × 7½. © All rights reserved. [Image: 4X27]