Helleborus lividus Ait. (incl. H. argutifolius Viv.) (Majorca) – A rare but increasing escape from cultivation. Locally probably more or less established. First recorded in 2011 in Nukerke and later also observed in Genk, Brussels (Jette), Menen, Nukerke, Antwerpen (Berchem), etc. Some records obviously refer to plants that established from discarded garden waste. In urban areas in Antwerp and Brussels Helleborus lividus was seen as seedlings. In coastal woodland in De Haan this species grows in a more natural area.
Helleborus lividus is fairly characteristic with its ternate leathery cauline leaves. It is the only representative of section Chenopus. It is a variable species and in the wild H. argutifolius Viv. (syn.: H. lividus subsp. corsicus (Willd.) Tutin), a native from Corsica and Sardinia, is more or less easily separated: its leaflets are more distinctly spine-toothed and it tends to be a larger plant (up to 1,2 m tall). Genuine H. lividus has leaflets with a few shallow teeth and rarely exceeds 50 cm. The latter also has leaflets with a conspicuously ‘marbled’ upper leaf surface (pale veins). Typical plants of both have been recorded in Belgium (see photos) but more or less intermediate plants also occur. These are probably hybrids (H. xsternii Turrill) (see also McLewin & Mathew 2000). It seems that species boundaries in this complex have considerably blurred and for that reason H. lividus is here treated as a single variable species, including hybrids.
Also elsewhere on the European continent, H. lividus is increasingly reported as an escape from cultivation in recent years (e.g., in the Netherlands, the British Isles; see Holverda & al. 2009, Stace 2010).
Selected references
Arrigoni P.V. (1979) Le piante endemiche della Sardegna: 40 - 53. Publ. Ist. Bot. Univ. Firenze n.s. 15 (425): 223-295.
Durand T. (1899) Phanérogames. In: De Wildeman E. & Durand T., Prodrome de la flore belge. A. Castaigne Editeur, Bruxelles: 1112 p.
Holverda W., van Moorsel R. & Duistermaat L. (2009) Nieuwe vondsten van zeldzame planten in 2005, 2006 en ten dele 2007. Gorteria 34: 1-40. [available online at: http://www.repository.naturalis.nl/document/568057]
McLewin W. & Mathew B. (2000) Hellebores: 8. Helleborus argutifolius, Helleborus lividus and Heleborus x sternii. New Plantsman 7(2): 95-102.
Nieto Feliner G. (1983) El Helleborus lividus y su publicacion original. An. Jard. Bot. Madrid 40(1): 277. [available online at: http://www.rjb.csic.es/jardinbotanico/ficheros/documentos/pdf/anales/198...(1)_277_285.pdf]
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.
Yeo P.F. (1986) The nomenclature of Helleborus lividus Aiton sens. lat. (Ranunculaceae). Taxon 35(1): 156-161.