A hybrid between R. pimpinellifolia and, it is now thought, R. sherardii, described from specimens collected in the ‘Western Isles of Scotland’. Plants with R. pimpinellifolia as the seed-parent take after that species in armature. Leaflets usually seven broadly ovate to almost orbicular or elliptic, more or less double-toothed, downy beneath. Rachis downy to almost glabrous, with straight or slightly curved small prickles and a few glandular bristles. Flowers solitary, on bristly peduncles rarely more than 1⁄2 in. long. Fruits roundish, bristly; sepals persistent, erect or reflexed, glandular on the back. The reverse cross gives a more robust plant, more or less intermediate between the parents.
This hybrid occurs in Scotland, N. Wales and N. England, the form with the burnet rose as the seed-parent being the commoner.
R. × sabinii Woods – A natural hybrid between R. pimpinellifolia and R. mollis. The commoner form, with the burnet rose as the seed-parent, resembles the above but the leaf-rachis has only a few short, curved prickles, the peduncles are longer, to 3⁄4 in. long, and the fruits are ovoid or urn-shaped, longer than wide, sparsely bristly, with erect sepals. It has more or less the same distribution in Britain as R. × involuta but is less common. The reverse cross is rare.
The hybrid R. pimpinellifolia × R. tomentosa is uncommon in Britain but has been collected in a few localities in S.E. England and the Midlands, the former being the seed-parent in all cases. The more indumented leaflets, hairy above and tomentose beneath serve to distinguish it from R. × involuta and R. × sabinii.
For further details, see R. Melville in C. A. Stace, Hybridisation and the Flora of the British Isles (1975), pp. 218-220, on which the above is largely based.