fistula (L.) = a pipe. Referring to the hollow culms.
WCM Protologue Reference:
Kunth, Enum. Pl. 3: 467 (1841)
Vegetative parts: plants tufted, 0.4–1.1 m tall, basal diameter 0.1–0.3 m, crown diameter 0.2–0.5 m, compact, without spreading rhizomes or stolons. Fertile culms unbranched, round (not compressed), distinctly hollow (distinguishing feature of this species - fistulose means hollow and cylindrical, like a pipe), smooth or finely rugulose, green or olivaceous, 0.3–1.1 m tall, diameter at base 1–3 mm, diameter at apex 0.8–2 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, 22–70 mm long, green with reddish-brown speckles in lower part, upper portion of sheath a deeper reddish-brown or tan with dense brown speckles, margins tan, upper 1/3 in colour and texture similar to the lower 2/3 or abruptly different from the base, and soon decaying, apical margins narrowly membranous, hyaline shoulders absent, apex, excluding the membranous lobes, acute. Sheath-mucro penicellate, straight and erect, 1.5–2.5 mm long. Males: male inflorescence with 50–100 spikelets or 101–500 spikelets or 501 and more spikelets, paniculate, 60–250 mm long, 15–50 mm wide. Male inflorescence spathes persistent, taller than spikelets, cartilaginous, spathellae (subtending the spikelets) are prominent. Male spathellae conspicuous, 5–30 mm long. Male flowers in spikelets. Male spikelets erect on stiff pedicels or sessile, undifferentiated, apex undifferentiated, 1.6–3 mm, 1–2.5 mm, with 2–5 flowers, pedicels shorter than the spikelets or as long as the spikelets, terete or angular. Male bracts shorter than flowers, 1.2–2 mm long, ovate or orbicular, rounded or obtuse or acute, chartaceous or cartilaginous, bract upper margin like body of bract, bract awn less than half as long as the bract body. Male flower 1–2 mm long. Male tepals sepals and petals the same rigidity, cartilaginous, elliptical, inner tepals longer than outer tepals. Male outer lateral tepals keeled or winged or as other tepals, glabrous. Anthers 1–1.4 mm long, included in the flowers. Females: female inflorescence interrupted or linear, 30–200 mm long, 10–25 mm wide, with 6–10 spikelets or 11–20 spikelets or 21–50 spikelets. Female spathes longer than the spikelets, obscuring spikelet, persistent, cartilaginous. Female spathellae conspicuous, 5–25 mm long. Female spikelet pedicel sparsely branching, undifferentiated, apex undifferentiated, 4.5–6.5 mm long, with 10–25 flowers, with 0 sterile bracts. Female bracts shorter than flowers, erect, 1–2 mm long, ovate or orbicular, rounded or obtuse or acute, cartilaginous, apical margin like rest of bract, same as body of bract, awn less than half as long as the bract body. Female flower 1.8–3 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 obtuse or acute, inner and outer whorls the same length. Female outer lateral tepals like other tepals or conduplicate, hidden by bracts, or bracts are shorter than flowers, 2–3 mm long. Female odd outer tepal oblong or elliptical, 2–3 mm long. Female inner tepals oblong, 2–2.5 mm long. Staminodes absent. Styles red, 3. Ovary with 1 locule, indehiscent. Fruit: indehiscent fruits with a softer ovary wall. Nut apex smooth, without a distinct cap, wall smooth or wall tuberculate, (1.56–)2.18(–2.8) mm long, (0.84–)1.1(–1.68) mm diam., shape in side view elliptical, shape in top view triangular in cross section, brown. Elaiosome absent.