50 Rhodora [Marcu 
2. When it duplicates the name of a class, order, family or genus, 
or a subdivision or species of the same genus, or a subdivision of the 
same species. 
3. When it is based on a monstrosity. 
4. When the group which it designates embraces elements alto- 
gether incoherent, or when it becomes a permanent source of confusion 
or error. 
5. When it is contrary to the rules of sections 4 and 6. 
Examples. — 1°. Carelia Adans. (1763) is a name which was applied by its 
author to a genus which had already received a valid name (Ageratum L. 
[1753] (synonym); similarly Trichilia alata N. E. Brown (in Kew Bull. [1896] 
p. 160) is a name which cannot be maintained because it is a synonym of T. 
pterophylla C. DC. (in Bull. Herb. Boiss. II, 581 [1894]).— 2. Tapeinanthus, 
a name given by Boissier to a genus of Labiatae was replaced by Thuspeinanta 
by Th. Durand, because of the existence of an earlier and valid genus, Tapein- 
anthus Herb. among the Amaryllidaceae (homonym). Similarly Astragalus 
rhizanthus Boiss. (Diagn. Pl. Or. ser. 1, II, 83 [1843]) was renamed A. cariensis 
Boiss. because of the existence of an earlier valid homonym, Astragalus 
rhizanthus Royle Illustr. Bot. Himal. p. 200 (1835). — 4°. The genus Uro- 
pedium Lindl. was based on a monstrosity which is now referred to Phragmo- 
pedilum caudatum Rolfe. — 59. 'The genus Schrebera L. derives its characters 
from the two genera Cuscula and Myrica (parasite and host) and must be 
dropped; and the same applies to Lemairea De Vr. which is made up of ele- 
ments taken from different families. Linnaeus described under the name of 
Rosa villosa a plant which has been referred to several different species and 
of which certain identification seems impossible; to avoid the confusion 
which results from the use of the name Rosa villosa, it is preferable in this 
case, as in other analogous cases, to abandon the name altogether. 
Art. 52. The name of an order, suborder, family or subfamily, 
tribe or subtribe, must be changed when it is taken from a genus 
which, by general consent, does not belong to the group in question. 
Examples. — If it were to be shown that the genus Portulaca does not 
belong to the family Portulacaceae, the name Portulacaceae would have to be 
changed.— Nees (in Hooker and Arnott, Bot. Beechey’s Voy. p. 237 [1836]) 
E the name T'ristegineae to a tribe of Gramineae, after the genus Tristegis 
ees (a synonym of the genus Melinis Beauv.). But Melinis (Tristegis) 
having been excluded from this tribe by Stapf (in Fl. Cap. VII. 313) and by 
Hackel (in Oesterr. bot. Zeiteshr. LI, 464), these authors have adopted the 
name Arundinelleae from the genus Arundinella. 
Art. 53. When a subgenus, a section or a subsection, passes as 
such into another genus, the name must be changed if there is already, 
in that genus, a valid group of the same rank, under the same name. 
When a species is moved from one genus into another, its specific 
epithet must be changed if it is already borne by a valid species of 
that genus. Similarly when a subspecies, a variety, or some other 
subdivision of a species is placed under another species, its name 
