Phalaris aquatica

1. Phalaris aquatica L. (syn.: P. tuberosa L., P. nodosa Murray; incl. P. elongata Braun-Blanq., P. hirtiglumis (Trab.) Baldini) (Medit.) – A very rare and usually ephemeral alien of obscure origin. Probably first recorded on levelled soil in the port of Antwerpen in 1998, perhaps as a grass seed alien (along with, among others, Trifolium alexandrinum). Not confirmed afterwards. A seemingly well-established population of unknown provenance was discovered in a ditch in Geel (Winkelomseheide) in 2008 (see also http://waarnemingen.be/waarneming/view/43242840). It was still present in 2015 and apparently easily survived the cold winter of 2010-2011. Phalaris aquatica is sometimes sown as pheasant food or cover (Clement 1981, Clement 1982). In general appearance – the perennial habit excepted – Phalaris aquatica is much reminiscent of the much more frequent P. minor but its glume wings usually are entire and its sterile floret slightly more hairy.

Phalaris aquatica is a fairly variable species. Plants with sparsely pubescent glumes and wider leaves have been segregated as Phalaris elongata (Baldini 1995). The exact taxonomic position of this taxon is unclear. It might be a mere ecotype of Phalaris aquatica (comm. R. Baldini). The Euro+Med Plantbase, on the contrary, recently accepted Phalaris elongata. The population from Geel belongs to this race.