pluri- (L.) = many, + stachys (G.) = spike. Thus "many-spikeletted", which does indeed describe the species.
WCM Protologue Reference:
Mast., Bot. Jahrb. Syst. 29(66): 12 (1900)
Vegetative parts: plants tufted, 0.6–1 m tall, basal diameter 0.05–0.2 m, crown diameter 0.2–0.6 m, compact, without spreading rhizomes or stolons. Fertile culms unbranched, smooth, olivaceous, 0.6–1 m tall, diameter at base 1–2 mm, diameter at apex 0.8–1.5 mm. Sheaths closely convoluted, 20–35 mm long, tan at base, gray towards apex, apical margins broadly chartaceous and soon decaying, hyaline shoulders absent, apex, excluding the membranous lobes, acute. Sheath-mucro absent or penicellate, straight and erect, 0–2 mm long, solid, greenish to tan at base, while apex is papery and decays. Males: male inflorescence with 50–100 spikelets or 101–500 spikelets, paniculate, 70–150 mm long, 20–50 mm wide. Male inflorescence spathes persistent, upper margins lacerated and largely decayed at anthesis, shorter than spikelets, chartaceous. Male flowers in spikelets. Male spikelets pendulous on flexible pedicels, linear or oblong, apex rounded, 6–15 mm, 4–5 mm, with 12–24 flowers, pedicels shorter than the spikelets, flattened. Male bracts as tall as flowers or taller than flowers, 2.5–4.5 mm long, oblong or ovate, acute, cartilaginous, bract upper margin like body of bract, bract awn minute or absent, brick red. Male flower 2.3–3 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 keeled or winged, glabrous. Anthers 1.2–1.7 mm long, included in the flowers. Pistillode absent. Females: female inflorescence paniculate or racemose, 50–130 mm long, 15–40 mm wide, with 6–10 spikelets or 11–20 spikelets or 21–50 spikelets or 51–100 spikelets. Female spathes longer than the spikelets, not obscuring spikelet, persistent (splitting and decaying), chartaceous. Female spikelet sessile or pedicel simple or pedicel sparsely branching, oblong (oblanceolate), apex rounded, 10–18 mm long, with 10–20 flowers, with 0 sterile bracts. Female bracts taller than flowers or at least twice as long as flowers, 6–8 mm long, oblong (lanceolate), acute, cartilaginous, apical margin like rest of bract, same as body of bract, awn minute or absent. Female flower 2–3.5 mm long, without a fleshy pedicel. Female tepals cartilaginous, glabrous and smooth, at least as tall as nut, wrapped around it and obscuring the surface, midrib flush with the tepal body, apices obtuse (inner) or acute (outer), inner and outer whorls the same length or inner whorl shorter than outer. Female outer lateral tepals keeled or winged, wings entire, as wide as body, 2–3.5 mm long. Female odd outer tepal oblong, 1.8–3.2 mm long. Female inner tepals ovate, 1.8–3 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 or oblong, narrower than long. Nut apex smooth, without a distinct cap, wall smooth, 1.3–2 mm long, 1–1.4 mm diam., shape in side view elliptical, shape in top view elliptical in cross section (with lateral ridges), tan (black at the top). Elaiosome absent.