persisto (L.) = remain constant, persist. It is not clear what aspect of the species Masters was referring to.
WCM Protologue Reference:
Mast., Bot. Jahrb. Syst. 29(66): 8 (1900)
Vegetative parts: plants tufted, 0.3–1 m tall, basal diameter 0.05–0.1 m, crown diameter 0.15–0.3 m, compact, without spreading rhizomes or stolons. Fertile culms unbranched, round (not compressed), solid or with a small central cavity, smooth or finely warty, green or olivaceous, 0.3–0.6 m tall, diameter at base 1–2.5 mm, diameter at apex 1–2.5 mm. Clusters of sterile branches at the nodes of the fertile branches absent. Sheaths more than 1 per culm, dropping off, with an abscission line present, loosely convoluted, 10–30 mm long, margins entire, tan with reddish-brown speckles, margins tan, apical margins narrowly membranous, hyaline shoulders absent, apex, excluding the membranous lobes, acute or obtuse. Sheath-mucro penicellate or hair-like, straight and erect, 0.1–0.5 mm long, the mucro is very small but noticable at the tip of the sheath, it is darker in colour and forms a clear extension of the midrib. Males: male inflorescence with 101–500 spikelets, paniculate, 80–250 mm long, 10–25 mm wide. Male inflorescence spathes persistent or caducous (spathes usually persistent), taller than spikelets, cartilaginous. Male spathellae inconspicuous or absent or conspicuous (a few of the spathellae are conspicuous), 7–14 mm long. Male flowers in spikelets. Male spikelets erect on stiff pedicels or sessile, ovate or undifferentiated, apex undifferentiated, 2.5–3.5 mm, 2–3 mm, with 1–4 flowers, pedicels shorter than the spikelets or as long as the spikelets, terete or angular. Male bracts shorter than flowers, 0.7–1.1 mm long, orbicular, rounded, chartaceous, bract upper margin like body of bract, bract awn minute or absent. Male flower 3.5–4.5 mm long. Male tepals sepals and petals the same rigidity, chartaceous, oblong or ovate, inner tepals longer than outer tepals. Male outer lateral tepals as other tepals, glabrous. Anthers 2–3 mm long, exserted from the flowers to included in the flowers. Females: female inflorescence interrupted or linear, 80–180 mm long, 10–20 mm wide, with 6–10 spikelets or 11–20 spikelets. Female spathes longer than the spikelets, obscuring spikelet, persistent, cartilaginous. Female spathellae inconspicuous or absent. Female spikelet pedicel sparsely branching, undifferentiated, 4.5–5.5 mm long, with 1–4 flowers, with 0 sterile bracts. Female bracts shorter than flowers, erect, 1–1.5 mm long, ovate, obtuse or acute, cartilaginous, apical margin membranous, paler than body of bract, awn minute or absent. Female flower 2–3.5 mm long, without a fleshy pedicel, six tepals. Female tepals cartilaginous, glabrous and smooth, at least as tall as nut, wrapped around it and obscuring the surface, midrib raised, margins entire, apices acute, inner whorl shorter than outer. Female outer lateral tepals like other tepals or conduplicate, hidden by bracts, or bracts are shorter than flowers, 1.5–2 mm long. Female odd outer tepal oblong or ovate, 1.5–2 mm long. Female inner tepals ovate, 2.5–3.5 mm long. Staminodes present. Styles white, 3. Ovary with 1 locule, indehiscent. Fruit: indehiscent fruits with a softer ovary wall. Nut apex smooth, without a distinct cap, wall smooth, (1.32–)1.98(–2.48) mm long, (0.6–)1.18(–1.68) mm diam., shape in side view ovate, shape in top view round in cross section, brown or black. Elaiosome absent.