LIST OF ILLUSTRATIONS 
Fig. 1. Winchell-Rotundifolia hybrid vines of 1913 in foliage. This photo¬ 
graph shows the tardy growth that is characteristic of this class of hybrids. 
Photographed May 16, 1919. Reduced. 
Fig. 2. A Winchell-Rotundifolia hybrid vine. This vine was grown from 
seed in the spring of 1913 and is the oldest living known hybrid between 
Euvitis and V. rotundifolia. Unpruned in the dormant stage, winter of 
1918-1919. Reduced. 
Fig. 3. Sections of two canes from the 1913 Winchell-Rotundifolia hybrid 
vine showing practically continuous pith, which is characteristic of the 
Rotundifolia parent species. Reduced. 
Fig. 4. Sections of canes from each of the two parents and of the hybrid 
vines. The cane at the left is V. rotundifolia (light male), the one in the 
center is Winchell (female parent), the one on the right is the hybrid. 
The Winchell cane shows the well defined diaphragms that interrupt the 
pith column at every node while the other two canes show no such dia¬ 
phragms. The hybrid cane, furthermore, exemplifies its hybrid nature in its 
relatively less zigzag growth, the slightly enlarged nodes, the internodes, 
which are intermediate in length, and the pith column whose relative diameter 
is intermediate between that of both its parents. Reduced. 
Fig. 5. A leafy shoot from the 1913 Winchell-Rotundifolia hybrid, show¬ 
ing its type of shoot, leaf and tendril. Reduced. 
Fig. 6. Three typical leaves representing both parents and hybrid. Upper 
leaf is from Winchell (female), lower right is from Rotundifolia (male) and 
lower left is from the hybrid. The size of the hybrid leaf is largely 
determined by the Rotundifolia parent while the character of the leaf is 
more intermediate. Reduced. 
Fig. 7. Types of flower-clusters represented by Winchell (perfect her¬ 
maphroditic but used as the female parent) on the left; hybrid (imperfect 
hermaphroditic) second; Scuppernong (imperfect hermaphroditic) third; and 
staminate Rotundifolia (male parent) on the right. The sizes of the flower- 
clusters in our native species of Vitis are sex-limited; the cluster of this 
hybrid vine which is an imperfect hermaphrodite, therefore, is smaller than 
that of either of its parents, it takes after the size of the flower-cluster that 
is associated with the imperfect hermaphroditic Rotundifolia vine and, 
therefore, is determined by the Rotundifolia species. Reduced. 
Fig. 8. Seeds from parental and hybrid vines; on the left are seeds from 
Winchell (female parent), on the right are typical Rotundifolia seeds (repre¬ 
senting the male parent), below are seeds from the hybrid vine. The general 
outline and type of the seeds from the hybrid vine evidently are determined 
by the Rotundifolia parent. Natural size. 
Fig. 9. Two types of flower-clusters found among the F x hybrid vines when 
Winchell is crossed with the perfect hermaphroditic Rotundifolia vine 1-1. 
The cluster on the left (perfect hermaphroditic) assumes the size of the per¬ 
fect hermaphroditic Rotundifolia vine, while the cluster on the right (imper¬ 
fect hermaphroditic) assumes the size of similar flower-clusters that are found 
on Rotundifolia vines. Reduced. 
Fig. 10. A sample of the pollen that is produced by the perfect hermaphro¬ 
ditic hybrid vines of Winchell-Rotundifolia parentage. Notice the three 
