Chondrilla juncea L. (incl. C. latifolia Bieb.) (Medit., C-Eur.) – A very rare, probably naturalizing alien. Obviously recently increasing. Discovered as an urban weed without obvious vector of introduction in the city of Gent in 2004 (gone in 2005, probably destroyed by weed killer). Recorded in 2007 from a coal mine heap in Zolder (a single specimen) but not confirmed subsequently. In 2010 scattered specimens were seen on two coal mine heaps in Genk (Klaverberg and Waterschei) where it seems to persist well (confirmed ever since). Chondrilla juncea is possibly unintentionally introduced (as a contaminant) on the occasion of the re-vegetation of the former coal mining sites in Limburg. In 2011 it was furthermore discovered in abundance by railway sidings and roadsides in the port of Antwerpen (Antwerpsebaan south of Delwaidedok). At this locality, Chondrilla juncea must have been present since several years and looks perfectly naturalized, despite the regular use of herbicides. In 2012 another small population was discovered in this area, east of the Kanaaldok, and several plants were found growing near an abandoned railway station in Kortrijk (confirmed subsequently). Finally, two plants were seen on a disused railway yard in the port of Ghent in 2013 and the species was also discovered - with Epilobium brachycarpum - in a railway yard in Arlon (Remacle 2014). Chondrilla juncea usually inhabits dry, sun-exposed, often stony places. In suitable habitats it will probably be able to naturalize.
The jizz of Chondrilla juncea (especially in the vegetative state) is very indistinct and the species might therefore possibly pass unrecorded.
As a native species, Chondrilla juncea reaches northern France. The recent increase of Belgian records could be interpreted as a natural range extension. However, most records are from highly artificial habitats (see above) and therefore most likely hazardous introductions.
 |
 |
 |
 |
 |
Selected literature:
Feder J. (2007) Verbreitung und Soziologie von Chondrilla juncea L. (Großer Knorpellattich) im Landkreis Gifhorn und im mittleren Niedersachsen (mit Bremen). Floristische Notizen aus der Lüneburger Heide 15: 17-27.
Knöppel A. (2009) Risfibbla – ny art för Sverige (Chondrilla juncea – new for Sweden). Svensk Bot. Tidskr. 103: 3-4. [available online at: http://sbf.c.se/www/pdf/103%281%29/knoppel.pdf]
Remacle A. (2014) Epilobium brachycarpum (Onagraceae) et Chondrilla juncea (Asteraceae), néophytes établis à Arlon (province de Luxembourg, Belgique). Dumortiera 105: 9-12. [available online at: http://www.br.fgov.be/DUMORTIERA/DUM_105/Dum_105_9-12_Epilobium_Chondrilla_Remacle.pdf]