Diplotaxis catholica

Diplotaxis catholica (L.) DC. (W Medit.) – A very rare and ephemeral alien. This species was discovered in quantity in 2016 on ground heaps and rough ground at the Ghent Grain Terminal at the Rodenhuizedok in the Ghent port area.
Diplotaxis catholica is much reminiscent of D. virgata and both may have been confused so far in Belgium. In contrast with the latter, it is almost glabrous (versus hirsute hairy, especially in the lower half) or has scattered conical trichomes on stems and leaves. Moreover, its sepals are clearly horned in bud (Martínez Laborde 1993).
Diplotaxis catholica is a fairly rare alien outside of its native area, known for instance from the British Isles (only historical records; Clement & Foster 1994) and Scandinavia (Karlsson 1997). It is also naturalized locally in Corsica (Tison & de Foucault 2014). It is a known agricultural weed (with Bayer Code dipca).

Selected literature:

Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
Karlsson T. (1997) Förteckning över svenska kärlväxter. Svensk Bot. Tidskr. 91: 241-560.
Martínez Laborde J.B. (1993) Diplotaxis. In: Castroviejo S. & al. (eds), Flora Iberica Vol. 4. Consejo Superior de Investigaciones Científicas, Madrid : 346-362. [available online at: http://www.floraiberica.es/floraiberica/texto/pdfs/04_072_57_Diplotaxis....
Tison J.-M. & de Foucault B. (coord.) 2014) Flora Gallica. Flore de France. Editions Biotope, Mèze : xx + 1196 p.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith