12 INTERNATIONAL RULES FOR BOTANICAL NOMENCLATURE 
based only on the enumeration of three species of the genus Ocimum 
without indication of characters. 
Article 39. The dateofa name, or of a combination of names, 
is that of their effective publication. In the absence of proof to 
the contrary, the date placed on the work containing the name 
or combination of names is regarded as correct. On and after 
takes effect only from 1882, when it was published with a descrip- 
ion glise, /.c., p. 211). There is some reason for supposing 
Vv 
1s assumed to be correct. The different parts of Willdenow’s 
Species Plantarum were published as follows :—Vol. i. 1798; vol. ii. 
ol. iii. 1, 1801; vol. iii. 
third volume of the Prodromus Flore Hispanice of Willkomm & 
Lange, the title-page of which bears the date 1880, was published 
in four parts—pp. 1-240 in 1874, pp. 241-512 in 1877, pp. 518-786 
1878, p. 787 to the end in 1880, and it is these dates which take 
elect. 
Recommenpations. Botanists will do well, in publishing, to 
conform to the following recommendations. 
XVI. Not to publish a name without clearly indicating 
whether it is the name of a family or a tribe, a genus or a section, 
a species or a variety, briefly, without expressing an opinion on the 
nature of the group to which they give the name. 
XIX. To ayoid publishing or mentioning in their publications 
unpublished names which they do not accept, especially if the 
persons responsible for these names have not formally authorized 
their publication. (See Recommendation XIV, e 
XX. When publishing new names in works written in a 
modern language (floras, catalogues, &c.), to publish simultaneously 
the Latin diagnoses which will make the names valid from the 
point of view of scientific nomenclature. 
XXI. To give the etymology of new generie names, and also 
of specific names when the meaning of the latter is not obvious. 
XXII. To indicate precisely the date of publication of their 
works, and that of the placing on sale or the distribution of 
named and numbered plants when these are accompanied by printed 
iagnoses. In case of a work appearing in parts, the last 
published sheet of a volume should indicate the precise dates at 
