Smilax rotundifolia L. (N-Am.) – An exceptional, locally naturalised escape from cultivation. Known since 1990 from woodland in a private estate in Kortessem (Jongenbos), scrambling up to 10m high in trees.
The plant from Kortessem was originally ascribed to Smilax rotundifolia but this determination was altered by Verloove & Lambinon (2008). On the sole basis of more or less terete stems (and in the absence of fruits) the plants were tentatively ascribed to Smilax excelsa L., the usual escape in western Europe (apart from the widespread Smilax aspera) (see Clement & Foster 1994). According to Alexander (1986), Smilax rotundifolia is readily distinguished by 4-angled stems and blue to black berries (vs. terete to slightly angled stems with red berries in S. excelsa). However, their distinction on the sole basis of stem characters might turn out to be problematic: Holmes (2002) describes Smilax rotundifolia with stems “terete to quadrangular”, while DeFilipps (1980) says stems “angled” for S. excelsa. Therefore, the location was visited once again in 2008 and berries were finally collected. They are blackish-blue and the plants from Kortessem definitively belong to Smilax rotundifolia.
Alexander J.C.M. (1986) Smilax. In: Walters S.M. & al. (eds.), The European Garden Flora, vol. 1. Cambridge University Press, Cambridge: 269-271.
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
DeFilipps R.A. (1980) Smilax. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 5. Cambridge University Press, Cambridge: 74.
Holmes W.C. (2002) Smilacaceae. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 26. Oxford University Press, New York-Oxford: 468-478.
Verloove F. & Lambinon J. (2008) Neophytes in Belgium: corrections and adjustments. Syst. Geogr. Pl. 78: 63-79.