180 
R. Ruggles Gates. 
In a study of the variations of tobacco in the East Indies, 
Lodewijks (1911) states that double flowers are the most common 
aberrations, although gigantism, fasciation and other types of 
change also occur. Doubles appear yearly on almost every 
plantation, and the doubling is of the hose-in-hose type. All parts 
of the plant are also changed, so that doubles can easily be 
distinguished before they come into bloom. The stem is zig-zag, 
shorter and not winged ; the leaves are very small and thicker 
owing to local outgrowths on their ventral surface ; the midrib is 
twisted, and the stigma shows similar growths, though to a less 
extent. All these peculiarities apparently result from a single 
mutation, and the type breeds true. In crosses with the normal the 
latter dominates almost without exception, and the F 2 gives a 3 : 1 
ratio (46S : 10D, 306S : 105D). It is a curious fact that the 
heterozygotes were distinguishable from pure singles by their 
leaves having outgrowths on the underside. Thus of the 306 
singles above, 204 were shown in this way to be heterozygous and 
102 SS. Again, in the F 2 from single X double the ratio was 
32S : 58DS : 31D. It is very interesting that in this set of 
mutant characters, the double flowers are wholly recessive and 
the leaf peculiarity at least partially dominant, though they behave 
as a unit in inheritance. 
In a work on the mountain cherries of Japan, in which is 
embodied an elaborate study of the group of plants which plays 
such a prominent part in the national life of that country, Miyoshi 
(1916) recognizes four species, Prunus serrulata Lindl., P .mutabilis 
Miyos., P. sachalinensis (Fr. Schm.) Miyos., and P.fruticosa Miyos., 
and a very large number of forms, especially of mutabilis (65) and 
servulata (68). Cultivated double varieties have been known for 
over a thousand years. A great number of forms have arisen in the 
intervening period, but only the best have been preserved and 
many old varieties have been lost. In Yoshino, the oldest and 
most famous cherry neighbourhood, trees have from time to time 
been planted from the neighbouring mountains for over a 
thousand years. At Koganei, near Tokyo, is the greatest assemblage 
of wild cherries, none of which show any influence of cultivation. 
There are three other main centres for cherry varieties, and many 
places noted for a local form or even a single tree, but the larger 
centres have been the source of new forms and races from time 
immemorial. 
