Machaerina Vahl
Type sp.: M. restioides (Swartz) Vahl from the West Indies.
Infl. an effuse often drooping panicle. Spikelets , 2–6-fld, 2–4 lowest fls setting fr. Glumes obscurely distichous to spiral. Hypog. bristles 6–3, or 0 (in N.Z. sp. 0). Stamens 3. Style-branches 3, style-base ± 3-winged or sharply 3-angled. Fr. with very thin brittle pericarp at maturity and a ± 3-winged us. long stipe, crowned by the persistent conspicuous style-base. Perennial herbs. Lvs us. basal, strongly laterally compressed, distichous, equitant at the base. Some 25 spp. from the West Indies, S. America, Hawaii, Malesia and the Pacific Is; one N.Z. sp.
The genus Cladium Browne sens. lat. was subdivided by Kükenthal (Fedde Repert. Spec. nov. Regn. veg. 51, 1942, 1–17, 139–193) into 3 subgenera: Eu-Cladium, Machaerina and Baumea. Further investigations by Koyama (Bot. Mag., Tokyo 69, 1956, 59–67), Kern (Acta bot. neerl. 8, 1959, 263–265) and Blake (Contrib. Qd Herb. no. 8, 1969, 22–30) have revealed new diagnostic characters so that Kükenthal's 3 subgenera may be regarded as distinct genera. Cladium sens. strict. is not represented in N.Z.; the principal features in which it differs from Machaerina and Baumea are: stamens 2; fr. seated on a truncate disk; culms hollow; lvs spirally arranged, dorsiventrally compressed and scabrid on the margins. The pollen type also differs: Cladium has 1 + 6 aperture type pollen; Machaerina has polyporate grains (Koyama op. cit.).
Some spp. placed in Machaerina have been described as or referred to Vincentia Gaud. (Freyc. Voy. Bot. 1829, 417; type sp. V. angustifolia Gaud. of Hawaii) but Koyama (op. cit.), Blake (op. cit.) and Bentham and Hooker (Gen. Pl. 3, 1883, 1066) agree that Vincentia differs from Machaerina only in lacking hypog. bristles.
