Article (magazine)  (2005)  Page(s) 452.  
 
Formation of spontaneous hybrids [with Rosa rugosa] has been reported to occur with three polyploid species in the British Isles...
R. canina = R. x praegeri Wolley-Dod
R. mollis Sm. = R. x mangii Eigner x Wissemann
R. caesia Sm.