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mollis Sm, while the combination gs, applies to the var. ccerulea 
Woods. The GS form is R. pseudo-rubiginosa Lej. This leaves 
the combination Gs unnamed, but such forms are not unknown 
and have been frequently noticed occurring with the other 
varieties. 
The group tomentosa is a more difficult one to deal with. It 
is usual, in this country at least, to divide it into three 
sub-groups according to the direction and relative persistence of 
the sepals. In R. omissa Desegl. the sepals ultimately become 
quite erect and persist until the fruit is ripe. On the other hand, 
the third sub-group, represented by R. scabriuscula Sm., includes 
those forms characterised by the possession of reflexed and early- 
deciduous sepals. An intermediate sub-group is that of R. 
subglobosa Sm .=R. Sherardi Davies, in which the sepals are 
spreading or no more than slightly ascending and they disarticulate 
before the fruit is fully ripe. The whole group is perhaps the most 
difficult one we have to classify and it would not be surprising to 
find that this difficulty is largely due to hybridisation and re¬ 
hybridisation among the different forms. An experimental 
investigation to discover whether R, subglobosa Sm. is not, in 
fact, a hybrid between R. omissa Desegl. and R. scabriuscula Sm. 
would be exceedingly valuable. 
We come, finally, to the section Pimpinellifolias containing 
R. pimpinellifolia L. which is one of the best-defined and perhaps 
least variable species we have. Essentially a plant of sandy sea- 
coasts, it is nevertheless not unknown from inland stations. Its 
habit, setigerous stems, and distinctive foliage are features which 
at once distinguish it from other members of the genus. If we 
consider leaf serration and the nature of the peduncles, using the 
same letters as before, then, of the four combinations, BS, Bs, bS, 
and bs, the last-mentioned is the commonest form and applies to 
R. pimpinellifolia. The bS form corresponds to R. spinosissima. 
The only variety with fully biserrate leaflets is R. Ripartii Desegl. 
which corresponds to the combination Bs. In Britain this plant 
is somewhat rare, but a faint biserration is fairly frequently seen 
in the type. Well-defined forms of the BS combination have not 
been recognised, although forms approaching it have been recorded 
without any distinctive name. 
In the theoretical analysis which has been attempted in the 
foregoing pages comparatively few characters have been taken into 
consideration. The selection of a few has been deliberate, as my 
main purpose has been rather to direct attention to the very high 
