Allium ramosum  

Allium ramosum L. (incl. A. tuberosum Rottler ex Spreng. (SE As.) – A very rare and ephemeral escape from or relic of cultivation. Recorded in 2010 on a quay bordering river Schelde in Antwerpen and in 2014 in Retie.
Allium ramosum and A. tuberosum are both widely cultivated as spice plant and transitional forms are known to exist (Fritsch 2015). Therefore, they are here treated as a single variable species, A. ramosum.

Selected literature:

Fritsch R.M. (2015) Checklist of ornamental Allium species and cultivars currently offered in the trade. Publication in the Internet at: http://www.ipk-gatersleben.de/fileadmin/content-ipk/content-ipk-institut....

Seregin A.P. & Korniak T. (2013) Allium ramosum L. (Amaryllidaceae), a neglected alien in the European flora and its oldest record from Poland. Phytotaxa 134(1): 61-64. [available online at: https://www.researchgate.net/publication/261876603_Allium_ramosum_L_Amar...