18 
JST. C. Agricultural Experiment Station 
The flower of Rathbun is very similar to that of Premo except that 
the pistils do not protrude from the flower bud. When Rathbun flowers 
are self-pollinated we usually get some fruit development, and this fruit 
may range all the w T ay from almost perfect to no fruit at all. 
In regard to the question of self-sterility of varieties of dewberries, 
however, the fact still remains that in many other varieties with healthy 
normal stamens, complete self-sterility exists. Hence, another solution 
of the question of sterility must be sought. 
Petalody in normal plants must not be confused in any way with 
Double Blossom (34th Ann. Bept. H. C. Agr. Exp. Sta., 1912, by 
Fig. 5. —Flowers of Rathbun, (blackberry-dewberry hybrid), showing very much 
weakened and reduced stamens. 
Reimer and Detjen and-Der; Agr. Exp. Sta. Bui. Ho. 93, by M. T. Cook), 
which is a disease that is caused by a parasitic fungus, Fusarium rubi 
(Winter). 
This fungus is frequently the cause of the development of unusually 
large numbers of petals in the flowers of some varieties, notably, Lucretia 
and Wilson. In fact, some of the affected blooms quite resemble a 
small white double rose. 
The real difference between a petaliferous bloom of a normal plant 
and a petaliferous bloom of one that is affected with Fusarium rubi 
is revealed in the production of fruit. Petaliferous flowers on otherwise 
