26 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
NOTES ON THE ORIGIN OF THE MOSS-ROSE. 
By Major C. C. Hurst, D.L., J.P., F.L.S., and Mabel 
S. G. Breeze, B.Sc. 
In 1908 experiments were undertaken at Burbage to investigate the 
genetics of certain variable species and garden hybrids of Rosa (Hurst, 
1 911).* These experiments were continued until the outbreak of 
war in 1914, when more urgent affairs demanded priority, and it 
was not until 191 9 that it was possible to resume the experiments 
and to prepare a report on what had been done. Among the many 
interesting problems in the genetics of Rosa, the question of the Moss- 
Rose presented itself as one of outstanding interest from many points 
of view. But before attacking the problem genetically it seemed 
necessary to trace as far as possible the history of the original Moss- 
Rose, its direct descendants, and its parent species. The following 
notes represent the more important results of these researches. 
Characters Peculiar to the Moss-Rose. 
The original Moss-Rose, R. muscosa of Miller (1768), appears to 
be identical in all its external characters with the old Cabbage-Rose, 
R. centifolia (Linnaeus, 1753), except that it possesses the following 
additional characters : The stems, branches, petioles, stipules, pedicels, 
peduncles, and calyx-tubes are densely covered with irregular aciculi 
and glandular branched bristles, while the sepals are copiously 
compound and covered on the back and edges with multitudinous 
branched gland-edged mossy processes, which give off a resinous or 
balsamic odour when bruised. In other words, the Moss-Rose differs 
from the Cabbage-Rose in its multiplicity of glandular organs. It is 
important, however, to note that the difference is not simply that of 
presence or absence of glands, for the Cabbage-Rose is glandular in 
parts, e.g. petioles, stipules, peduncles, and sepals. Nor is it a difference 
merely of many or few glands, nor even of more extended or less 
extended glandular areas. It is also a difference of compound or 
simple glands, and these are multitudinous partly on account of the 
extension and increased density of the glandular areas, but mainly 
through the multiplicate branching of the gland-bearing organs (cf. 
Blondel, 1889). 
Whether the presence of these additional characters in the Moss- 
Rose entitles it to specific rank, or whether it should be regarded as 
a variety of R. centifolia L. is a question concerning which systematists 
are divided. Miller, who appears to have been the first to describe the 
* Namss and dates in brackets refer to the Bibliography at the end of this 
paper. 
