43.1. A name of a taxon below the rank of genus is not validly published unless the name of the genus or species to which it is assigned is validly published at the same time or was validly published previously.
Ex. 1. Binary designations for six species of "Suaeda", including "S. baccata" and "S. vera", were published with descriptions and diagnoses by Forsskål (Fl. Aegypt.-Arab.: 69-71. 1775), but he provided no description or diagnosis for the genus: these were not therefore validly published names.
Ex. 2. Müller (in Flora 63: 286. 1880) published the new genus "Phlyctidia" with the species "P. hampeana n. sp.", "P. boliviensis" (= Phlyctis boliviensis Nyl.), "P. sorediiformis" (= Phlyctis sorediiformis Kremp.), "P. brasiliensis" (= Phlyctis brasiliensis Nyl.), and "P. andensis" (= Phlyctis andensis Nyl.). These were not, however, validly published specific names in this place, because the intended generic name "Phlyctidia" was not validly published; Müller gave no generic description or diagnosis but only a description and a diagnosis of the new species "P. hampeana". This description and diagnosis did not validate the generic name as a descriptio generico-specifica under Art. 42 since the new genus was not monotypic. Valid publication of the name Phlyctidia was by Müller (1895), who provided a short generic diagnosis and explicitly included only two species, P. ludoviciensis Müll. Arg. and P. boliviensis (Nyl.) Müll. Arg. The latter names were validly published in 1895.
Note 1. This Article applies also when specific and other epithets are published under words not to be regarded as generic names (see Art. 20.4).
Ex. 3. The binary designation "Anonymos aquatica" (Walter, Fl. Carol.: 230. 1788) is not a validly published name. The correct name for the species concerned is Planera aquatica J. F. Gmel. (1791), and the date of the name, for purposes of priority, is 1791. The name must not be cited as "P. aquatica (Walter) J. F. Gmel."
Ex. 4. Despite the existence of the generic name Scirpoides
Ség. (1754), the binary designation "S. paradoxus"
(Rottbll, Descr. Pl. Rar.: 27. 1772) is not validly published
since "Scirpoides" in Rottbll's context was a
word not intended as a generic name. The first validly published
name for this species is Fuirena umbellata Rottb. (1773).