Red Grass

This species is closely related to Themedu triandra Forssk, a widely distributed species which grows in the warm and tropical regions of the world.

This is a highly polymorphic, predominantly apomictic species with a wide range of chromosome numbers.

The name Themeda arguens (Linnaeus) Hackel has been misapplied to this species in Yunnan. True T. arguens is not yet known from China. It occurs from Thailand and Vietnam to Australia, and can be distinguished by its reddish culms, very large, spathate fascicles with awns 7–9 cm, and longer callus 3–4 mm. It also differs from T. triandra by its glabrous leaf sheaths, blunter leaf blades, and homogamous spikelets consisting only of the lower glume.

Themeda triandra subsp. japonica (Willd.) Koyama, Grass. Jap. Neighb. Reg. 452. 1987. Culm slender, about 1.5 mm in diameter. Blade linear, less than 10 cm long by 3 mm wide, basal margins with glandular hairs; ligule chartaceous, 1-2 mm long, truncate, minutely ciliate on upper part and back. Spikelets paired, dimorphic, with 2 pairs of empty spikelets at base, forming a compound false panicle, interrupted by involucres; each empty spikelet covered with long glandular hairs on lower glume. The upper pedicellate, 1 /2 the width of the lower. Lower spikelet sessile, pubescent, about 5 mm long. Glumes coriaceous, as long as the spikelet: the lower linear-lanceolate, hirsute on back; the upper oblong, 2-keeled, margins inrolled and glabrous; lower lemma membranous, lanceolate, acute, about 3 mm long; upper lemma minute, membranous, about 2.5 mm long, apex prolonged into a long and hispid awn about 3.5 mm long. Caryopsis about 3 mm long, oblong; embryo linear, 1/2 the length of the caryopsis.

Perennial from a knotty rootstock. Culms tussocky, yellowish, usually farinose near nodes, 0.5–1.5 m tall. Leaf sheaths usually hispid with tubercle-based hairs; leaf blades 10–50 × 0.4–0.8 cm, glabrous or pilose, finely acuminate; ligule 1–2 mm, truncate, ciliate. Compound panicle lax, open, with spaced, often nodding spathate fascicles; spathes and spatheoles narrowly lanceolate, glabrous or thinly to densely tuberculate-hispid, innermost 2–3.5 cm. Raceme composed of a triad of 1 sessile and 2 pedicelled spikelets above the involucre of 2 homogamous pairs. Homogamous spikelets all sessile, arising at same level, staminate, both glumes present, 7–14 mm, oblong-lanceolate with lateral scarious wings, glabrous or hispid with tubercle-based hairs. Sessile spikelet 5–7 mm; callus 1.5–3 mm, pungent, brown bearded; lower glume dorsally rounded, dark brown, glossy, hispidulous in upper 1/3, smooth below; awn 3.7–7 cm. Pedicelled spikelet 7–12 mm, male or barren. Fl. and fr. Jun–Dec. 2n = 20, 40, 50, 60, 70, 80.

Distributed in China, Korea and Japan.

All warm and tropical regions.

Anhui, Fujian, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, India, Indonesia, Japan, Korea, Malaysia, Myanmar, Nepal, Philippines, Sri Lanka, Thailand, Vietnam; Africa, SW Asia, Australia].

2900-4100 m

Dry mountain slopes, roadsides, forest margins; 100–3000 m.

Anthistiria japonica Willdenow; Themeda barbinodis B. S. Sun & S. Wang; T. japonica (Willdenow) Tanaka; T. tri-andra var. japonica (Willdenow) Makino.