Bromus hordeaceus L.
soft brome
Annual, greyish green tufts, 10-100 cm. Leaf-sheath villous with long, soft hairs; upper sheaths sometimes glabrous. Ligule 0.5-1.5 mm, denticulate, abaxially short-hairy. Leaf-blade (1.5)-3-18 cm × (1)-1.5-5 mm, flaccid, velvety with soft, short hairs; tip subacute. Culm erect or geniculate at base, internodes minutely pubescent. Panicle (1.5)-2.5-15 cm, erect, ± contracted; branches pubescent, bearing 1-few spikelets; sometimes panicle reduced to a single spikelet. Spikelets 1.5-3 cm, 4-12-(16)-flowered, ovate to oblong, greyish green or purplish. Glumes subequal, acute, membranous, ± closely pubescent; lower 4.5-7.5 mm, 3-5-nerved, ovate or oblong-lanceolate, upper 5.5-8.5 mm, 5-7-nerved, elliptic. Lemma 6.5-10.5 mm, 7-nerved, rounded, papery with prominent nerves, obovate to elliptic, shortly pubescent throughout or ± glabrous below, or rarely entirely glabrous or very rarely scabrid; margins hyaline, flat, overlapping, usually narrow; awn 3-8 mm. Palea slightly < lemma, keels with sparse short stiff hairs sometimes interspersed with minute hairs. Callus glabrous. Rachilla minutely pubescent. Anthers 0.5-1.5-(2.5) mm. Caryopsis 4.5-6.5 × 1.5-2 mm.
N.; S.: throughout; K., Three Kings Is, Ch. Roadsides and waste land.
Naturalised.
Indigenous to Europe and western Asia; now naturalised in temperate regions of both Hemispheres.
This sp. was long known worldwide as B. mollis L. Smith, P. Watsonia 6: 327-344 (1968), resolved the uncertainty involving the application of the earlier name B. hordeaceus. He also demonstrated that in Britain the hybrid B. ×pseudothominii P.M.Sm. (B. hordeaceus × B. lepidus) was comon in disturbed habitats and distinguished from B. hordeaceus by the usually glabrous, shorter lemmas, 6.5-8 mm, and by the caryopsis usually = palea. This hybrid is also found in Europe, western Asia, and North Africa. A high proportion of N.Z. material has short lemmas but only very rarely are the lemmas entirely glabrous; B. hordeaceus is treated here as an aggregate of B. hordeaceus sens. strict. and B. ×pseudothominii, and the description includes both.
