Giant Reed

A form with striped leaves (var. versiocolor Stokes) cultivated in Taiwan and Japan.
[Distinguished by general appearance from two other large grasses with plumelike panicles: Neyraudia reynaudiana (Kunth) Keng., Burma reed or silk reed, and Phragmites australis (Cav.) Steud. The following characters will also separate the three: Phragmites has naked lemmas; Arundo has hairy lemmas and a naked rachilla; Neyraudia has naked lemmas and a hairy rachilla. All three species grow around canals.]

Forms with variegated leaf blades are sometimes cultivated in gar-dens, e.g., var. versicolor (Miller) Stokes (Arundo versicolor Miller), with longitudinally green- and white-striped leaf blades. Arundo donax var. coleotricha refers to a wild variant with pubescent leaf sheaths.

The culms have many uses, including light construction, basket making, matting, musical pipes, and ornaments.

Arundo donax is a plant of wet habitats but Bor (Grasses Burma Ceyl. Ind. Pak. 415) stated that it will grow in dryish places when once established. Cattle will browse its young leaves but it is not of much account as a fodder grass. In Europe it is extensively cut to make mats, trays and baskets and the Romans used the stems for pens. It is sometimes used for making paper but is commercially of less value than Phragmites australis.

Considerable difficulty may be experienced in distinguishing immature plants of Arundo, Neyraudia and Phragmites, and dissecting the spikelets will be of little use. Phragmites can be distinguished by the silky beard at the bases of the lowest panicle branches which is absent from the other two genera. The ligule of Arundo is membranous while that of Phragmites and Neyraudia is a fringe of hairs. The leaves of Arundo are very much broader than in the other genera and are conspicuously cordate or rounded at the base.

Tall coarse perennial tufted with short thick rhizome. Culm about 1-3 cm in diameter. Blades 2-4 cm wide, the margins scabrid; ligule 2 mm long, fimbriate on upper margin, siliceous on dorsal side; sheath usually longer than the internode, glabrous or subdensely pubescent (var. coleotricha Hackel). Panicle ample, 30-70 cm long, axiss strigose at nodes. Spikelets 3-4-flowered or more, terete, 10-15 mm long; glumes chartaceous, lanceolate, siliceous apex with short awn or acute; the lower glume about 12 mm long, 3-5-nerved, rarely 4-nerved, covered with a few silky hairs on the backside; the uppe glume about 10 mm long, 3-5-nerved; lemma 10-12 mm long, 5-nerved middle nerve prolonged into a 3 mm long awn, 2 lateral awn slightly cuspidate, basal part densely covered with long silky hairs which are nearly as long as the lemma; palea about 5 mm long, 2-keeled, the margins ciliate, apex truncate; lodicules 2, truncate, nerved, stamens 3. anther 2.5 mm long.

Robust reed from a thick knotty rhizome. Culms very stout, erect, 2–6 m tall, 1–1.5 cm in diam., unbranched or with bamboolike clusters of slender branches from nodes. Leaf sheaths longer than internodes, usually glabrous except long pilose at mouth; leaf blades 30–60 × 2–5 cm, margins scabrous, tapering to a slender filiform apex; ligule 0.7–1.5 mm. Panicle 30–60 cm, dense, usually purplish; branches 10–25 cm, ascending. Spikelets 10–15 mm, florets 2–5; glumes narrowly lanceolate, 8–12 mm, 3–5-veined, lower glume acute, upper glume sharply acuminate; lemmas linear-lanceolate, 8–11 mm, 3–7-veined, dorsal hairs 5–6 mm, apex minutely bidentate with 1–2 mm awnlet from sinus, lateral veins also shortly extended; palea 1/2 length of lemma body. Fl. and fr. Oct–Dec.

Perennial, with creeping woody rhizomes. Culms erect, up to 5 m high. Leaf-blades conspicuously distichous, linear-lanceolate, rounded or cordate at the base, 30-60 cm long, 2.5-5 cm wide, glabrous, smooth, long-attenuate at the tip. Panicle 30.60 cm long and 5.8(10) cm wide. Spikelets 10-15 mm long; glumes subequal, lanceolate to narrowly lanceolate, (8-)10-13 mm long, the lower a little shorter than the upper; lemmas lanceolate, (6)8.5-13 mm long, 3-5-nerved, 3 of the nerves produced as short aristae, hairy all over the back below the middle with hairs up to 7 mm long.

Mediterranean region, tropical Asia. Introduced into New World.

Distribution: Pakistan (Baluchistan, Punjab, N.W.F.P. & Kashmir); Mediterranean region eastwards to Burma; North Africa; introduced into many parts of the World.

2100-2440 m

Fl. & Fr. Per.: June - December.

River banks and other damp places, but it will also grow when planted in dryish habitats. Fujian, Guangdong, Guizhou, Hainan, Hunan, Jiangsu, Sichuan, Xizang, Yunnan, Zhejiang [Afghanistan, Bhutan, Cambodia, India, Indonesia, Japan, Kazakhstan, Laos, Malaysia, Myanmar, Nepal, Pakistan, Tajikistan, Thailand, Turkmenistan, Uzbekistan, Vietnam; N Africa, C and SW Asia, S Europe; widely introduced elsewhere].

Aira bengalensis (Retzius) J. F. Gmelin; Amphidonax bengalensis (Retzius) Nees ex Steudel (1854), not Roxburgh ex Nees (1836); Arundo bengalensis Retzius; A. coleotricha (Hackel) Honda; A. donax var. coleotricha Hackel; Donax arundinaceus P. Beauvois; D. bengalensis (Retzius) P. Beauvois; Scolochloa donax (Linnaeus) Gaudin.