NAMES of hybrids
H.5.1. The appropriate rank of a nothotaxon is that of the postulated or known parent taxa.
H.5.2. If the postulated or known parent taxa are at unequal ranks, the appropriate rank of the nothotaxon is the lowest of these ranks.
Note 1. When a nothotaxon is designated by a name at a rank inappropriate to its hybrid formula, the name is incorrect in relation to that hybrid formula but may nevertheless be correct, or may become correct later (see also Art. 52 Note 4).
Ex. 1. The combination Elymus ×laxus (Fr.) Melderis & D. C. McClint. (in Watsonia 14: 394. 1983), based on Triticum laxum Fr. (Novit. Fl. Suec. Mant. 3: 13. 1842), was published for hybrids with the formula E. farctus subsp. boreoatlanticus (Simonet & Guin.) Melderis × E. repens (L.) Gould, so that the combination is at a rank inappropriate to the hybrid formula. It is, however, the correct name applicable to all hybrids between E. farctus (Viv.) Melderis and E. repens.
Ex. 2. Radcliffe-Smith published the nothospecific name Euphorbia ×cornubiensis Radcl.-Sm. (in Kew Bull. 40: 445. 1985) for E. amygdaloides L. × E. characias subsp. wulfenii (W. D. J. Koch) Radcl.-Sm., but the correct nothospecific name for all hybrids between E. amygdaloides and E. characias L. is E. ×martini Rouy (Ill. Pl. Eur. Rar.: 107. 1900); later, he published the appropriate combination E. ×martini nothosubsp. cornubiensis (Radcl.-Sm.) Radcl.-Sm. (in Taxon 35: 349. 1986). However, the name E. ×cornubiensis is potentially correct for hybrids with the formula E. amygdaloides × E. wulfenii W. D. J. Koch.
H.5A.1. When publishing a name of a new nothotaxon at the rank of species or below, authors should provide any available information on the taxonomic identity, at lower ranks, of the known or postulated parents of the type of the name.