Rescuegrass

Native of South America; introduced to many countries as a forage grass and naturalized in the central alpine region of Taiwan since 1960s.

This species is widely introduced as a winter forage (Rescue Grass) and is now adventive in most temperate countries.

Bromus catharticus (Bromus unioloides) and Bromus willdenowii are segregates from an imperfectly known South American complex. The temptation to call Asian material anything other than Bromus catharticus should be resisted until the complex as a whole is more fully understood.

Annuals, biennials or perennials. Culms ascending, 34-87 cm tall, 3 mm wide. Leaf-blades chartaceous, linear, 21-32 cm long, 5-7 mm wide, sharp at apex, veins conspicuous, puberulous to glabrous above, glabrous beneath. Sheath villous to glabrous. Ligule membranous, tongue- or triangular-shaped, rounded to acute at apex, 3 mm long. Inflorescence an open panicle, 13-31 cm long. Spikelets with 4-9 florets, elliptical, 27-28 mm long, 5-6 mm wide, strongly laterally compressed. Pedicels minutely hispid. Lower glumes subcoriaceous, minutely hispid, lanceolate, sharp at apex, 12-14 mm long, 7-nerved. Upper glumes coriaceous, broadly lanceolate, sharp at apex, 13-15 mm long, longer than 10 mm, 11-nerved, minutely strigose. Florets 19 mm long, with rachilla. Lemmas coriaceous, broadly lanceolate, margins not inrolled, acute at apex, 19 mm long, awnless, 11-nerved, minutely hispid on nerves. Paleas membranous, linear oblong, acute at apex, 8-10 mm long, 2 -nerved, ciliate on nerves. Callus glabrous. Caryopsis linear-oblong, 7 mm long, hilum linear.

Annual. Culms erect or geniculately ascending, 60–100 cm tall, ca. 5 mm in diam. Leaf sheaths pubescent; leaf blades 30–40 cm × 4–6 mm, scattered pubescent; ligule ca. 2 mm. Panicle lax, oblong in outline, 10–40 cm; branches ca. 10 cm, scabrid, each bearing 1–3 spikelets. Spikelets ovate-oblong, laterally compressed, 15–30 × 8–10 mm, florets 6–11, overlapping; rachilla internodes not visible, ca. 2 mm, scabrid; glumes narrowly lanceolate, lower glume 10–12 mm, upper glume slightly longer than lower glume; lemmas 15–20 mm, keeled, 11-veined, veins scabrid, apex mucronate; palea narrow, ca. 1/2 as long as lemma, keels ciliate. Anthers 0.3–0.6 mm. Fl. May, fr. Sep. 2n = 28, 42, 58.

Short-lived perennial tussock grass; culms erect or geniculately ascending, up to ± 1 m high. Leaf-blades up to 30 cm long and 8 mm wide; sheaths glabrous or pubescent. Panicle oblong, 10-40 cm long, loose. Spikelets oblong-ovate, 6-12 flowered, 16-40 mm long, strongly laterally compressed, the lemmas closely overlapping and concealing the short intemodes; glumes narrowly lanceolate in side view, the lower 10-15 mm long, a little shorter than the upper, accuminate, the lemmas narrowly lanceolate in side view, the lower 15-20 mm long laterally ,fattened and sharply keeled, herbaceous with hyaline margins, 9-13-nerved, scaberulous on the nerves, minutely 2-toothed with an awn-point up to 3 mm long from between the teeth; palea shorther than the lemma, ciliolate on the keels; anthers 0.3-0.6 mm long.

Distribution: Pakistan (Punjab & N.W.F.P.; introduced); a South American species widely introduced as a winter forage species under the name “Rescue Grass”, and now found as an escape in most temperate countries.

Shady ditch sides, introduced. Guizhou, Hebei, Jiangsu, Nei Mongol, Taiwan, Yunnan [native to South America].

Bromus unioloides Kunth, H. B. K., Nov. Gen. Sp. 1: 151. 1816; Osada, Illust. Grass. Jap. Enl. Ed. 396. 1993.

Bromus unioloides Kunth; Schedonorus unioloides (Kunth) Roemer & Schultes; Serrafalcus unioloides (Kunth) Sampaio; Zerna unioloides (Kunth) Lindman.