Bromus squarrosus L. (syn.: B. wolgensis Fisch. ex Jacq.) (Euras., N-Afr.) – A very rare and ephemeral alien. Much decreasing and only exceptionally seen nowadays, usually as a grain alien.
Bromus squarrosus and B. japonicus are closely related and often very much alike (see for instance Acedo & Llamas 2005, Oja & Paal 2007). The former usually has a racemose inflorescence with rather few, large, drooping spikelets at maturity. Lemmas are distinctly rhombic in outline with sharp marginal angles around the middle. The awn is usually inserted at least 2 mm below lemma apex. The inflorescence of Bromus japonicus on the contrary always is a panicle, often with numerous, smaller spikelets. Lemmas are only slightly rhombic in outline and margins are less sharply angled (angle above middle). The awn is most frequently inserted ca. 2 mm below lemma apex.
 |
 |
Selected literature:
Acedo C. & Llamas F. (2005) Consideraciones taxonómicas acerca de algunas especies anuales de Bromus; sect. Squarrosi nova. Bull. Soc. Hist. Nat. Toulouse 141(2): 43-48.
Oja T., Jaaska V. & Vislap V. (2003) Breeding system, evolution and taxonomy of Bromus arvensis, B. japonicus and B. squarrosus (Poaceae). Plant Syst. Evol. 242: 101-117.
Oja T. & Paal J. (2007) Multivariate analysis of morphological variation among closely related species Bromus japonicus, B. squarrosus and B. arvensis (Poaceae) in comparison with isozyme evidences. Nordic J. Bot. 24(6): 691-702.
Verloove F. & Vandenberghe C. (1999) Nieuwe en interessante voederadventieven voor de Belgische flora, hoofdzakelijk in 1998. Dumortiera 74: 23-32.