The species is a perennial, tufted grass with short, robust rhizomes.[3] Lateral branches lacking.[4] Flowering culms range from 5.5 to 70 cm (2.2 to 27.6 in), occasionally reaching 100 cm,[3] and were originally described by Étienne-Émile Desvaux (Desvaux) as 2–2½ feet tall.[1]
Leaf sheaths are closed and scabrous;[3] Desvaux noted them as tightly appressed to the stem.[1] Ligules are oblong, scarious, and lacerated, measuring 3–6 mm,[3] consistent with Desvaux measurement of nearly 3 lines (≈6 mm).[1]
Blades are linear, coriaceous, flat or folded, 4 to 10 cm (1.6 to 3.9 in) long × 2–8 mm wide,[3] whereas Desvaux described them as 2 to 4 inches (5.1 to 10.2 cm) inches long × 1 line wide (≈2 mm).[1] Both accounts note scabrous surfaces and margins, with Desvaux emphasizing a yellowish color and mucronate apex, and the modern revision describing the apex as abruptly navicular.[1][3]
The panicle is narrow and pauciflowered, 10 to 15 cm (3.9 to 5.9 in) long × 1–1.5 cm wide,[3] compared to Desvaux "nearly 6 inches (15 cm) inches, sparse, lax, inclined."[1] Spikelets are 4–7 mm long, 1–3‑flowered,[3] consistent with Desvaux account of 1–3 fertile flowers plus a rudiment of a sterile one.[1]
Glumes are unequal, oval, keeled, and obtuse; the lower 1‑veined and shorter, the upper 3‑veined and nearly equaling the floret,[3] matching Desvaux description.[1] Lemmas are 3.5–4.6 mm long, 5‑veined, lanceolate, glabrous,[3] while Gay described them as oval‑elongated, concave‑keeled, obtuse, somewhat trigonal, and 5‑nerved.[1]
Lodicules (paired, rudimentary scales below the ovary of a grass flower) are oblong with a sharp lobe,[3] consistent with Desvaux "oblong, not ciliate, with a long acute lobe."[1] Anthers measure 2.2–2.8 mm,[3] a feature not noted by Desvaux. The caryopsis is about 2 mm, yellowish, elliptical,[3] whereas Desvaux described it as elliptical, triangular‑compressed, and yellowish.[1]
