Vorster (Proschowsky) No year - Catalan P (1990) Festuca × souliei Saint-Yves, the Correct Name for the Hybrid between F. eskia and F. gautieri (Poaceae). Taxon 39(4): 661-662. doi: 10.2307/1223388.
There is no corrections for Butyagrus nabonnandii yet.