Euphorbia humifusa Willd. (syn.: Chamaesyce humifusa (Willd.) Prokh.) (As.) – A very rare but locally naturalized alien. Chiefly seen as a weed in botanical gardens (see also Galera & Sudnik-Wójcikowska 2010). First seen in 1880 in the former botanical garden in Leuven. Subsequently recorded in the botanical garden of Brussels in 1900 and more recently also in the botanical garden of Liège (persisting there for at least 30 years) (Jongepier & Robbrecht 1986). At present perhaps only known from two localities: in the Botanic Garden in Meise where Euphorbia humifusa is present since at least 1980 (Jongepier & Robbrecht l.c., Ronse 2011) and very well established. And in 2017 it was also detected in the Botanic Garden in Ghent.
So far, only glabrous forms (var. glabra (Thell.) S.Z. Liou) have been recorded in Europe.
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| Selected literature: |
Galera H. & Sudnik-Wójcikowska B. (2010) Central European botanic gardens as centres of dispersal of alien plants. Acta Soc. Bot. Polon. 79(2): 147-156. [availabe online at: http://pbsociety.org.pl/journals/index.php/asbp/issue/view/16/showToc]
Hügin G. (1997) Die Gattung Chamaesyce in Deutschland. Ber. Bayer. Bot. Ges. 68: 103-121.
Hügin G. (1998) Die Gattung Chamaesyce in Europa. Feddes Repert. 109(3-4): 189-223.
Hügin G. (1999) Verbreitung und Ökologie der Gattung Chamaesyce in Mitteleuropa, Oberitalien und Südfrankreich. Feddes Repert. 110(3-4): 225-264.
Jongepier J.-W. & Robbrecht E. (1986) Een “nieuwe” vondst van Euphorbia humifusa in België. I.F.B.L. Driemaandelijks contactblad 4(2): 16-19.
Lienenbecker H. & Lienenbecker I. (2007) Breitet sich die Niederliegende Wolfsmilch (Euphorbia humifusa) bei uns aus? Natur und Heimat (Münster) 67(2): 55-56.
Ronse A. (2011) External neophytes. In: Hoste I. (ed.), The spontaneous flora of the National Botanic Garden of Belgium. Scripta Botanica Belgica 47: 219 p.