Hybridism and Classification in the Genus Rosa. 167 
pollen in R. rubiginosa ( R. Eglanteria), this remarkable pollen- 
sterility being attributed to hybridisation. All the British forms of 
R. Eglanteria , except var. jenensis Schulze, have strongly hispid 
peduncles, and are usually differentiated according to whether the 
main prickles are distinct from or gradually merge into the acicles 
and by the ultimate direction and relative persistence of the sepals. 
All these varying features may be the result of various crossings, 
although I am at present quite unahle to suggest a possible parentage 
for the aggregate R. Eglanteria. 
The members of the small group micrantha show a 
taller and more arching habit recalling that of R. canina L. The 
stems do not present any admixture of acicles with the main 
prickles. The peduncles are glandular hispid in all the British forms 
except var. Briggsii Bak. R. Hystrix Bak. may be distinguished 
from the type and from var. permixta Ddsegl. by its smaller leaflets, 
while the type may be distinguished from the last-mentioned form 
by the absence of prickles from the flowering branches. 
The group of R. agrestis is also a small one and runs very 
close to that of R. micrantha , its members differing primarily in 
having smooth peduncles. They are small leafleted forms and it 
does not appear possible to segregate them satisfactorily, except 
perhaps on the basis of leaf pubescence, the presence of which 
marks off R. sepium, var. pubescens Rouy from the type of R. 
agrestis (=R. sepium Thuill.) which has glabrous leaflets. 
The sub-section Villosae may be regarded as comprising two 
groups only, one corresponding to R. villosa , L. of which R. mollis 
Sm. is the representative species in Britain, the other group being 
known under the name of R. tomentosa Sm. The members of the 
two groups vary considerably in habit, from low erect bushes to 
large, arching forms. The prickles are uniform, slender as a rule, 
straight or somewhat falcate. The leaflets are biserrate, very 
hairy, often softly tomentose and generally glandular, often decidedly 
so as in Rubiginosae forms, but the glands have a resinous not a 
fragrant odour. 
R. mollis Sm. is a tolerably well-defined species, at least as an 
aggregate, reaching its greatest frequency in the North of Britain. 
It varies chiefly in the amount of glandular development of the 
leaves and in the hispidity of the peduncles. To take these two 
characters only, we find that all the four theoretical combinations 
have been recognised, GS, Gs, gS, and gs, three of them having 
been named. The form gS, may be regarded as the type of R, 
