Rescuegrass

Foodplant / miner
larva of Agromyza bromi mines leaf of Ceratochloa cathartica
Other: sole host/prey

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

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.

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

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.

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.

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.

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

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

A variable annual or short-lived perennial.

Occasional

Originating from South America, but now naturalised in many parts of the world.

Annuals, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly closed, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence lax, widely spreading, branches drooping, pendulous, Inflorescence with 2-10 branches, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelet 3-10 mm wide, Spikelets with 3-7 florets, Spikelets with 8-40 florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets dis articulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes distinctly unequal, Glumes shorter than adjacent lemma, Glumes keeled or winged, Glumes 4-7 nerved, Glumes 8-15 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma glabrous, Lemma apex dentate, 2-fid, Lemma awnless, Lemma mucronate, very shortly beaked or awned, less than 1-2 mm, Lemma with 1 awn, Lemma awn less than 1 cm long, Lemma awn subapical or dorsal, Lemma awns straight or curved to base, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea keels winged, scabrous, or ciliate, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear, Caryopsis hairy at apex .

Bromus catharticus is a species of brome grass known by the common names rescuegrass, grazing brome, prairie grass, and Schrader's bromegrass. The specific epithet catharticus is Latin, meaning cathartic. The common name rescuegrass refers to the ability of the grass to provide forage after harsh droughts or severe winters. The grass has a diploid number of 42.

It is native to South America but it can be found in other places, including Europe, Australia and North America, as an introduced species.