1907] On the Vienna Rules of Nomenclature 49 
medium Ledeb. (Ind. Hort Dorp. [1822]), regarded as a variety of L. Salicaria 
L., must be called L. Salicaria var. gracilius Turez. (in Bull. Soc. Nat. Moscou, 
XVII, 235 [1844], not L. Salicaria var. intermedium Koehne (in Engl. Bot. 
Jahrb. I, 327 [1881]). In all these cases names which are in accordance with 
the old law of Alphonse de Candolle must give place to older names and 
combinations. 
Recommendations. Authors who make the changes discussed in article 
49 should note the following recommendations in order to avoid a change 
of name in case of a change of rank. 
XXIX. 1°. When a sub-tribe becomes a tribe, when a tribe becomes a 
subfamily, when a subfamily becomes a family, ete., or when the inverse 
changes occur, do not alter the root of a name but only the termination (-inae, 
-eae, -oideae, -aceae, -ineae, -ales, etc.), unless, in the new position one of the 
obstacles indicated in the articles of section 7, supervenes, or the new designa- 
tion becomes a source of error, or there is some other serious reason against it. 
20 When a section or a subgenus becomes a genus, or the inverse changes 
take place, retain the old names, unless this results in two genera of plants 
having the same name, or the existence of two subdivisions of the same name 
in the same genus, or one of the obstacles indicated in the articles of section 
7 supervenes. 
3°. When a subdivision of a species becomes a species or the inverse change 
occurs, retain the original epithets, unless this results in two s ecies bearing 
the same name in the same genus, or two subdivisions bearing the same name 
in the same species, or unless any of the obstacles indicated in section 7 super- 
venes. 
Section 7. On names that are to be rejected, changed or modified. 
Art. 50. No one is authorised to reject, change or modify a name 
(or combination of names) because it is badly chosen, or disagreeable, 
or another is preferable or better known, or because of the existence 
of an earlier homonym which is universally regarded as non-valid, 
or for any other motive either contestable or of little import. (See 
also art. 57.) 
Examples. — This rule was broken by the change of Staphylea to Staphylis, 
Tamus to Thamnos, Mentha to Minthe, Tillaea to Tillia, Vincetoricum to 
Alexitoxicon; and by the change of Orobanche Rapum to O. sarothamnophyta, 
O. Columbariae to Ò. columbarihaerens, O. Artemisiae to O. artemisiepiphyta. 
All these modifications (which are contrary to Art. 50) must be rejected.— 
The name Diplomorpha Meissn. in Regensb. Denkschr. ITI, 289 (1841) must 
not be substituted for the generic name Wickstroemia Endl. Prodr. fl. Norfolk., 
p. 47 (1833) because of the earlier homonyms Wi(c)kstroemia Schrad. Goett. 
gel. Anz., p. 710 (1821) and Wi(c)kstroemia Spreng. in Vet. Akad. Handl. 
Stockh. 1821, p. 167, t. 3, for the former is merely a synonym of the genus 
Laplacea Kunth (1821) and the latter of a subdivision of the genus Eupatorium 
L. (1753). 
ED LLnastons. See on the subject of homonyms recommendations 
Vb and XIV} which suggest that cases of this kind should be avoided for the 
future. 
Art. 51. Every one should refuse to admit a name in the following 
cases: 
1. When the name is applied in the plant kingdom to a group 
which has an earlier valid name. 
