40.1. In order to be validly published, names of hybrids of specific or lower rank with Latin epithets must comply with the same rules as names of non-hybrid taxa of the same rank.
Ex. 1. "Nepeta xfaassenii" (Bergmans, Vaste Pl. Rotsheesters, ed. 2: 544. 1939, with a description in Dutch; Lawrence in Gentes Herb. 8: 64. 1949, with a diagnosis in English) is not validly published, not being accompanied by or associated with a Latin description or diagnosis. The name Nepeta xfaassenii Bergmans ex Stearn (1950) is validly published, being accompanied by a Latin description.
Ex. 2. "Rheum xcultorum" (Thorsrud & Reisaeter, Norske Plantenavr.: 95. 1948), being there a nomen nudum, is not validly published.
Ex. 3. "Fumaria xsalmonii" (Druce, List Brit. Pl.: 4. 1908) is not validly published, because only the presumed parentage F. densiflora x F. officinalis is stated.
Note 1. For names of hybrids of the rank of genus or subdivision
of a genus, see Art. H.9.