WildBristol.uk - Discovering Wildlife in Bristol

Stace 4:

Bromus racemosus L. (B. commutatus Schrad.) - Smooth Brome.

Culms erect, to 1m; panicle fairly open, varying from rather narrow and erect to drooping to 1 side at maturity, with many branches longer than spikelets; lemmas 7-11mm, glabrous (rarely hairy), with straight awn 3-10mm; 2n=14, 28. Native; grassy places, waysides and rough ground, especially in damp rich meadows; locally frequent in Central and Southern Britain, over-recorded, very scattered grass-seed casual elsewhere in British Isles. B. racemosus has more leathery lemmas than B. hordeaceus and allies; this is an important diagnostic character which, although difficult to describe, is easy to use with experience. B. commutatus (Meadow Brome) is often treated as a separate species, with a more diffuse panicle, longer panicle branches (mostly >4 versus mostly <4cm), longer spikelets (15-30 versus 10-18mm) and lemmas (7.5-11 versus 7-9mm), and shorter anthers (1.3-2.5 versus 1.5-3.5cm), but all intermediates exist (sometimes recorded as hybrids) without any bimodality evident. Varietal rank might be appropriate.

Key:

• Panicle more or less lax, with ≥4 pedicels longer than spikelets
• Lemmas rather coriaceous, with obscure veins