530 Allgemeines. 



The genera of Linnaeus' Species Plantarum (1753) are 

 to be typified through the citations given in the Genera 

 Plantarum (1754). 



Note. — The Species Plantarum contains no generic refe- 

 rences, but the 1754 edition oi the Genera Plantarum was evi- 

 dently prepared at the same time and was in eiiect a comple- 

 mentary volume of the same work. It accords much more nearly 

 than other editions with the treatment followed in the Species 

 Plantarum, and thus makes it possible to retain more of the 

 Linnaean generic names in their current application. 



Examples. — Cypripedium L. Sp. PI. 95 1 , a genus adopted 

 from Tournefort with a change of his name Calceolus, is typified 

 by Cypripedium Calceolus, the only species common to both 

 authors; Senecio L. Sp. PI. 866, a genus adopted from Tourne- 

 fort, is typified by the fourth species, Senecio vulgaris, which 

 is the first of Tournefort's species that occurs also in the Senecio 

 of Linnaeus. 



d) When a prebinomial generic name is displaced by the 

 publication of a generic name within binomial usage, 

 the application of the displaced name to a species under 

 the new generic name designates the type. 



Example. — Dianthus L. Sp. PI. 409, a genus adopted 

 from Tournefort with a change of his name Caryophyllus, is 

 typified by Dianthus Caryophyllus L,. one of the fifteen original 

 species of Linnaeus. 



e) The application to a genus of a former specific name 

 of one of the included species, designates the type. 



Examples. — Amsonia Walt. Fl. Car. 98 (1788), is typified 

 by Tabernaemontana Amsonia L., one of its two original species; 

 Sordaria Ces. and De N. Comm. Soc. Critt. Ital. 1 : 225 (1863), 

 is typified by Sphaeria Sordaria Fr., one of its twelve original 

 species. 



f) To avoid change in the current application of a Linnaean 

 generic name, a well-known economic species may be 

 selected as the type, in accordance with the principle 

 stated by Linnaeus (Phil. Bot. 197. 1751): „Si genus 

 receptum, secundum jus naturae et artis in plura dirimi 

 debet, tum nomen antea commune manebit vulgatissi- 

 mae et officinali plantae." 



Examples. — Poa L. Sp. PI. 66, is typified by P. pratensis 

 L., the commonest of its original species ; Mollugo L. Sp. PI. 

 89, is typified by M. verticillata L., the commonest of its original 

 species. 



Section V. Rejection of Names. 



Canon 16. A name is rejected when preoccupied (homonym). 



a) A specific or subspecific name is a homonym when it 



has been published for another species under the same 



generic name. Two subspecies of the same genus shall 



not retain the same name. 



Examples. — Acer saccharinum Wang. Amer. 36 pl. 2 f. 26 

 (1787), is a homonym of Acer saccharinum L. Sp. PI. 1055(1753); 

 Vaccinium myrtilloides Hook. Fl. Bor. Am. 2: 32 (1834), is a 

 homonym of Vaccinium myrtilloides Michx. Fl. Bor. Am. 1 : 234 

 (1803), and is rejected whether the latter species is regarded as 

 distinct or not; Juncus nodosus megacephalus Torr. Fl. N. Y. 2: 

 326 (1843), is a homonym of Juncus megacephalus M. A. Curtis, 



