1. Polypogon maritimus Willd. [syn.: P. monspeliensis var. maritimus (Willd.) Coss. et Durieu] (Medit.) – A very rare and usually ephemeral alien, formerly recorded once as a wool alien in the Vesdre valley (Verviers, 1911). Recorded in 2004 as a casual grain alien in the port of Gent. From 1999 onwards found in sand-raised sites in the port of Antwerpen in similar habitats like Polypogon monspeliensis and perhaps often confused with the latter. Known from the Potpolder in Lillo (right bank of river Schelde) since 1999 and still present there in 2006. In 2006 and 2008 also discovered in similar habitats on Linkeroever (left bank of river Schelde). In 2007 furthermore recorded in abundance on a sand-raised site in Ghlin-Baudour near Mons (main population soon afterwards destroyed but regularly recorded in nearby localities subsequently). In 2014 also discovered in large quantities in Olmen, furthermore in Eindhout and Mol. An up-to-date overview of Belgian records is available here: http://waarnemingen.be/soort/view/133589. Polypogon maritimus apparently has been able to become locally naturalized in recent times and might have been overlooked in similar places elsewhere in Belgium (see Verloove & al. 2008 for more details). Finally, it is also sometimes introduced in plant nurseries with imported olive trees and palms (Hoste & al. 2009).
In general habit it is much reminiscent of Polypogon monspeliensis (perhaps sometimes a little more slender and often purple-tinged) but is easily distinguished on floral characters (see identification key).
Hoste I., Verloove F., Nagels C., Andriessen L. & Lambinon J. (2009) De adventievenflora van in België ingevoerde mediterrane containerplanten. Dumortiera 97: 1-16.
Verloove F. (2002) Ingeburgerde plantensoorten in Vlaanderen. Mededeling van het Instituut voor Natuurbehoud n° 20: 227 p.
Verloove F., De Beer D., Van de Vijver B. & Suys W. (2008) Polypogon maritimus, een miskende neofyt in België. Dumortiera 93: 26-28.