34 
EEVISION OF THE SECTION TOMENIOSA OF THE 
GENUS ROSA. 
By A. Desegltse* 
If, in a series of species forming a natural group, one compares the 
first of the series with the last, it will certainly be found that they are 
easily distinguished ; but if the first and second are compared, their 
resemblances will often appear more striking than their differences. 
One ought not, however, on this account, to unite them, for, if this be 
done, the third must be united to the second, and so on to the last of 
the series ; and this reunion of all the species into one, though appear- 
ing absurd, would however he only logical. Differences in individuals 
are at once explained by differences of locality and of age, but such a 
superficial examination does not admit of a satisfactory comparison of 
the forms upon which a number of species have been established. 
The species of the section Tomtntosa are met with almost every- 
where, and numerous specimens exist in all herbariums of any size, but, 
when one ventures to distinguish them, the difficulty experienced arises 
no doubt to some extent from the close affinity of the forms, but much 
more from the imperfection and obscurity of their diagnoses. 
If the modern school has been reproached for hastily establishin 
species often on a single difference, the same reproach may be as forci- 
bly applied to the ' lumpers,' who ignore, without examination, their 
differences. To know even a little of what is around us, one 
must persevc ringly and methodically examine the very objects them- 
selves, for nature is a better guide than man. Whatever opinion be 
held in regard to species, one must thoroughly study the natural forms ; 
they must be analysed, described, and classified, and science will 
eventuallv give them their true rank. 
Section Tomentosa, Desegl. Naturalist (1865), vol. i. p. 313.-^7- 
hsa, Eesser, Enum. Fl. Yolhynise, etc., p. 60. Canina (pars), Seringe 
in DC. Prod. vol. ii. p. 611. Diadylce trib. Orlhoacantha, Godet, Fl. 
Jura, p. 204. 
1. Rosa vestita, Godet. Fl. Jura, p. 210. 
2. R. Jrduennensis, Crepin, Notes sur PL rares et crit. de la 
* Abstract of a paper from vol. xx. of the c Memoires de la Societe Acade- 
mique d'Angers,' with translations of the characters of the species found in 
Britain. 
cr 
a 
