16 
N. C. Agricultural Experiment Station 
clusters to be cross-fertilized were securely covered with fine cloth 
bags, that were made especially for this work. This in most cases was 
done before any of the blossoms had opened, but where any had 
opened these were removed from the cluster before it was covered with 
the bag. In all the earlier work the flower clusters of the male vines 
were also covered before any of them had opened, and the pollen was 
collected from time to time as it was needed. In the later work this 
operation was facilitated by bringing canes with several flower clusters 
into the laboratory, placing them in water, and screening them from 
flies and other insects to prevent contamination of the various different 
lots. The pollen was collected from day to day as the flowers opened, 
and stored in glass test-tubes until it was needed. In our self-sterility 
studies we had already found that the pollen from the cultivated va¬ 
rieties is worthless and impotent, hence it was not necessary to remove 
Fig. 6.—Flower clusters from male vines. Cluster on left from an average 
male vine ; cluster on the right from an exceptionally good male vine. 
any of the stamens or anthers from these varieties before applying the 
pollen from the male plants. This knowledge was to us of great mo¬ 
ment, for it saved us much valuable time. The actual work of cross¬ 
pollination requires considerable time, for only a few flowers open on 
the cluster each day. It is therefore necessary to go over each lot of 
flowers about three times a week, until all of the flowers have opened, a 
period usually lasting from two to four weeks. During each operation 
the bags were carefully removed from the flower clusters, the pollen 
taken from the test-tubes with a camel’s hair brush and applied to the 
stigmas of the flowers, and then the bags were replaced. Each cane was 
carefully labeled, indicating the cross made, and a corresponding rec¬ 
ord was kept in a note book. As soon as the fruit ripened in the fall it 
was collected, the seeds removed, dried, and stored. It was necessary 
to collect the ripening fruit at regular intervals of time for, as previously 
stated, the ripening season of this grape lasts several weeks. (See Figs. 
4 to 9 inclusive.) 
