28 
The Bulletin 
flower clusters without setting fruit when heavily pruned and crowded 
together as are these vines. 
The point is well illustrated in the last table, where all of the eight 
vines shed some of their flower clusters, and three out of the eight pro¬ 
duced no fruits at all inside of the bags. As the season of 1915 was an 
exceptionally unfavorable one for fruit production in the experimental 
vineyard, these negative results must be looked upon as indicative only, 
but a further trial or investigation doubtless will prove these same vines 
to be self-fertile like the others. All of the vines that set no fruit in 
the bags were subsequently examined as to the character of their pollen, 
and in no case did this prove to be anything but normal. 
From these results we conclude that upright stamens in rotundifolia 
grape flowers are always associated with viable pollen, and, if the pistils 
are normally developed, with a certain degree of self-fertility of the 
vine. 
It might be of interest to know that along with the character of the 
pollen, and the type of stamens, there is correlated a third character, 
namely, that of size of flower cluster. The staminate vines produce com¬ 
paratively large flower clusters; the hermaphrodite vines that bear up¬ 
right stamens produce flower clusters of a similar size, while the her¬ 
maphrodite vines with the reflexed stamens generally produce small 
flower clusters. 
Notwithstanding the fact that the flower clusters of the three different 
types of vines vary considerably among themselves, it is always possible 
to determine with comparative ease and accuracy what the type of 
stamen and the character of pollen will be while the vine is still in bud. 
When hermaphrodite vines that bear the reflexed type of stamen are 
crossed with staminate vines, the resulting progeny can be separated and 
grouped according to their sexes by means of the size of their respective 
flower clusters. In like manner the progeny of hermaphrodite vines that 
bear the reflexed type of stamen, when crossed with pollen from her¬ 
maphrodite vines that bear the upright stamens, can be separated and 
grouped according to the character of their pollen by nothing more than 
their characteristic flower clusters. 
These correlated characters are of considerable importance to the 
rotundifolia grape breeder, because by means of them a comparatively 
early selection and segregation of vines can be made with respect to 
normal viable pollen and self-fertility. 
VI. Similarity Between Flower Clusters That Are Borne on 
Hermaphrodite Vines With Upright Stamens and Those 
That Are Borne on Staminate Vines. 
As the staminate vines when in bud, and before any flowers have 
opened, can be readily distinguished from the imperfect hermaphrodite 
vines by the difference in the size and shape of their respective flower 
clusters (see Fig. 7), so in like manner the perfect hermaphrodite vines 
