platy- (G.) = broad, + pterus (G.) = winged. In reference to the dispersal units, which are the broadest winged in the genus.
WCM Protologue Reference:
Kunth, Enum. Pl. 3: 429 (1841)
Vegetative parts: plants tufted, 0.6–1 m tall, basal diameter 0.05–0.2 m, crown diameter 0.2–0.5 m, compact, without spreading rhizomes or stolons. Fertile culms unbranched, smooth or punctate or finely rugulose (sometimes culms dry sulcate), olivaceous, 0.6–1 m tall, diameter at base 0.8–1.6 mm, diameter at apex 0.5–1.2 mm. Sheaths closely convoluted, 40–60 mm long, pale brown, apical margins broadly chartaceous and soon decaying, hyaline shoulders absent, apex, excluding the membranous lobes, acute. Sheath-mucro absent. Males: male inflorescence with 11–20 spikelets or 21–50 spikelets, paniculate, 30–80 mm long, 15–40 mm wide. Male inflorescence spathes persistent, taller than spikelets, chartaceous. Male flowers in spikelets. Male spikelets pendulous on flexible pedicels, oblong or ovate, apex rounded, 4–10 mm, 3–6 mm, with 12–28 flowers, pedicels shorter than the spikelets, flattened. Male bracts taller than flowers, oblong or ovate, acute, chartaceous, bract upper margin like body of bract, bract awn minute or absent, brick red. Male flower 2–3 mm long. Male tepals sepals and petals the same rigidity, chartaceous or cartilaginous, oblong, inner and outer tepals the same length. Male outer lateral tepals conduplicate, glabrous. Anthers 1.7–1.9 mm long, included in the flowers. Pistillode absent. Females: female inflorescence racemose, 30–50 mm long, 12–30 mm wide, with 2–5 spikelets (rarely a solitary spikelet). Female spathes longer than the spikelets, not obscuring spikelet, persistent, chartaceous. Female spikelet pedicel simple, obtriangular, apex truncate, 10–30 mm long, with 4–16 flowers, with 0 sterile bracts. Female bracts taller than flowers, 8–20 mm long, linear or oblong (very narrowly obtriangular), acute, chartaceous, apical margin like rest of bract, same as body of bract, awn minute or absent. Female flower 6–9 mm long, without a fleshy pedicel. Female tepals chartaceous or cartilaginous, glabrous and smooth, at least as tall as nut, wrapped around it and obscuring the surface, midrib flush with the tepal body, apices acute, inner whorl shorter than outer. Female outer lateral tepals keeled or winged, wings entire, wings lateral sepals decurrent, without grooves, wider than body, exserted past bracts and overlapping with one another, 6–9 mm long. Female odd outer tepal oblong, 4–4.5 mm long. Female inner tepals ovate, 3.5–4.5 mm long. Staminodes absent. Styles plumose, white, 1. Ovary with 1 locule, indehiscent. Fruit: indehiscent fruits with a softer ovary wall. Perianth presence on fruits persistent, winged. Shape of winged dispersal unit orbicular. Nut apex smooth, without a distinct cap, wall smooth, (2–)2.37(–2.6) mm long, (1.32–)1.73(–2) mm diam., shape in side view elliptical, shape in top view elliptical in cross section (with lateral ridges), brown. Elaiosome absent.