Bromus intermedius Guss. (Medit.) – An exceptional and ephemeral alien. Recorded only once on a dump in Berchem (Antwerpen) in 1952.
This collection was initially ascribed to Bromus scoparius. With this species it shares the papery, pubescent lemmas and curved-out awns at maturity. However, it is readily distinguished by the much less contracted inflorescence (with at least some spikelets on distinct branches), wider lemmas with angled margins, more hairy leaf sheaths, etc.
A similar species, Bromus optimae H. Scholz, was recently described from Cyprus (Scholz 1999). It has longer anthers (3-5 mm vs. 0,5-2 mm) and wider lemmas (4-5 mm vs. 3-4 mm) with 7-9 veins (vs. at most 7 veins). It is perhaps best accepted as a subspecies of Bromus intermedius (subsp. optimae (H. Scholz) H. Scholz; see Scholz 2008).
Selected literature:
Scholz H. (1999) Bromus optimae, a new annual brome-grass (Gramineae) from Cyprus. Bocconea 11: 85-87.
Scholz H. (2008) Some comments on the genus Bromus (Poaceae) and three new species. Willdenowia 38: 411-422.