B. ‘Arborea S’ sometimes appears on-line in the format of a cultivar name; the “S” is an informal tag given to this Sect. Sphaerocarpium plant resembling B. arborea distributed from Strybing Arboretum. The plant is reputed to be self-incompatible and has the corolla tube slightly longer than is usual for B. arborea, which together suggest it is a hybrid. The name should not be established, since it gives a (likely) false impression of an origin of the cultivar in B. arborea (see Rec. 21J of the 2009 ICNCP).