112 Mr. Woops on the British Species of Rosa. 
yellow-flowered Roses are perhaps constant in their colour; but 
this is by no means the case with the other species. ‘The globu- 
lar fruit in some divisions of the genus appears to be important ; 
in others it is extremely uncertain. If the bristly fruitstalks are 
ever of any value, it can only be when they are used very cau- 
tiously to separate one or two allied species in particular subdi- 
visions. > | | 
The characters which appear to me most constant in this genus 
are the presence or absence of setæ on the stems; the prickles 
straight or hooked, equal or unequal; the tendency towards the 
formation of the upper stipule without leaves, or at least with 
leaves of fewer folioles, and expanding into bractez. Next to 
these are the simple or compound form of the leafits of the ca- 
lyx, and the simple or compound serratures of the leaves. In the 
latter subdivisions 1 have made use of the shape and flatness 
or hollowness of the leaflets; and sometimes, though un willingly, 
I have been obliged to depend on the pubescence, not finding 
any other describable character to discriminate plants whose 
difference of habit seemed to announce the necessity of sepa- 
ration. 
This arrangement is not without its disadvantages, principally 
on account of the deciduous nature of the setz in two, or perhaps 
in three, families of the genus. Of these, however, R. cinnamomea 
is the only British plant; and a moderate attention to the descrip- 
tion will easily teach the difference between this plant and Rosa 
villosa, the only species with which a specimen devoid of setae is 
in danger of being confounded. ` 
ROSA. 
