Bot. Abh. Beobacht.: 44 (1787).- Type: Herb. Mertens, unknown (syn- LE).
Bromus rigidus Roth, Bot. Mag. (Römer & Usteri) 4(10): 21 (1790);
Bromus rubens Linn. var. rigidus (Roth) Mutel, Fl. Franç. Herbor. 4: 133 (1837);
Anisantha rigida (Roth) Hylander, Upsala Univ. Arsskr. 7: 32 (1945);
Anisantha diandra (Roth) Tutin ssp. rigida (Roth) Tzvelev, Zlaki SSSR: 223 (1976);
Bromus diandrus Roth ssp. rigidus (Roth) O. Bolòs, Masalles & Vigo, Collect. Bot. (Barcelona) 17: 96 (1988);
Bromus madritensis Cav. ex Kunth, Enum. Pl. 1: 419 (1833).
Regional litterature: FTEA: 67 (1970); Pl. Sudan & S Sudan: 121 (2015).
Description:
* Annual of 35–80 cm high. Culms erect or spreading, pubescent below the inflorescence. Leaves 10–25 cm long and 4–8 mm wide; ligule 3-5 mm; sheaths loosely hairy.
* Inflorescence in loose or erect contracted panicles, 10-25 cm long but variable in size. Branches scabrid, hairy, bearing erect few to many spikelets, nodding.
* Spikelets loosely 5–8-flowered, oblong to wedge-shaped, 2–5 cm long; callus oblong, 1 mm long, obtuse. Glumes finely pointed, the lower subulate, 15–23 mm long, 1–3-nerved, the upper narrowly lanceolate, 20–32 mm. long, 3–5-nerved. Lemmas narrowly lanceolate in side view, 22–36 mm long, herbaceous with hyaline margins, 7-nerved, scabrid, acuminately bilobed, awned from 4–7 mm. below the tip; awn 3–6 cm. long, straight, scabrid; palea shorter than the lemma, sparsely and stiffly ciliate on the keels. Anthers 2–3, 0.8–1.5 mm long.
Distribution West Africa: Cape Verde, Sudan.
Distribution world-wide: Morocco, Algeria, Tunesia, Libya, Egypt, southern Europe, W Asia, introduced in E and southern Africa, New Zealand, Australia and the Americas.
Note: invasive species. Bromus diandrus and B. rigidus are very closely related. A re-assessment of the taxonomy and nomenclature of the annual taxa within the mainly Mediterranean/southwestern Asiatic Bromus section Genea is given by Sales (1993) in which B. sterilis, B. diandrus and B. rigidus are considered as varieties of one species while recognizing that they have often been treated as separate species in recent floras. In this treatment Saarela, J.M., Peterson, P.M. & Váldes-Reyna, J. (2014) has been followed, considering B. rigidus as synonymous..