Flora of New Zealand Series

Type sp.: C. fascicularis Labill. of Australia.

Fls ∞, in a complex "spike" within 2 ± opp., unequal, glume-like bracts. Partial infls (pseudanthia) 1–8–(20) within each bract, each with 1–3, or 0 hyaline scales. ♂, 1 or 0 per pseudanthium with 1-celled anther. ♀, (1)–2–20 in each pseudanthium, ± connate and superposed in 1–2 rows, all styles free or ± connate at the base. Fr. dehiscing longitudinally. Small herbs, tufted and annual, or perennial and cushion-forming. Lvs linear-filiform and crowded at base of stem, or, in perennial cushion plants, densely imbricate up the stem, with stiff, terete, compressed or channelled lamina. Flowering stems slender, terminated by the 2 floral bracts and "spike". About 25 spp. chiefly in Australia, extending through Malaysia to Southeast Asia. Three N.Z. spp. are endemic and C. strigosa occurs also in Australia.

R. Brown (Prodr. 1810, 253) described 3 Australian spp. under the genus Alepyrum differing from Desvauxia (= Centrolepis) in having no "glumes" and only 1 or few "flowers" within each glume-like bract or "spathe". Hieronymus (Abh. naturforsch. Ges. Halle 12, 1873, 209, 217) transferred Brown's 3 spp. of Alepyrum to Centrolepis but still retained the name Alepyrum for two perennial subantarctic spp. described by Hooker (1844). Because Hieronymus's use of Alepyrum was thus unacceptable Dandy (J. Bot., Lond. 70, 1932, 331) proposed the name Pseudalepyrum to cover the N.Z. spp. of Alepyrum sensu Hieronymus. Gilg-Benedict (Pflanzenfam. ed. 2, 15A, 1930, 27–33) separated Centrolepis and Alepyrum (Pseudalepyrum) on vegetative characters; Centrolepis being annual, Pseudalepyrum perennial. This separation is unsatisfactory because the type sp. of Centrolepis, C. fascicularis, is perennial. The difference in number of pseudanthia which was first used by R. Brown as a criterion on which to separate the genera is also unsatisfactory. In the endemic N.Z. spp. of Centrolepis (Pseudalepyrum) a glume-like floral bract encloses only 1–(2) pseudanthia, each with 1–4–(6) fls, and though in most spp. of Centrolepis the floral bract encloses several pseudanthia, each with 10 or more fls, there are still some Australian spp. which have just as low numbers of pseudanthia and fls as are found in N.Z. Ding Hou (Flora Malesiana ser. 1, 5, 1957, 423) has concluded that "all . . . species assigned to Pseudalepyrum . . . clearly belong to Centrolepis."