Limits in Hybridization 
23 
4. Observations and Discussions. 
While attempting the work of finding limits in the hybridization of 
Yitis rotundifolia with related species and genera, the following obser¬ 
vations and deductions were made. 
a. In order to adhere strictly to the letter and object that is before 
ns, only pure species so far as possible were used. Whenever varieties 
of Euvitis are mentioned in connection with species, Yinifera excepted 
because these constitute the species, the evidence thus secured should be 
looked upon as pertaining to the variety only. Thus the varieties Con¬ 
cord and Lutie have been utilized in hybridization work with Y. labrusca. 
Yow it is generally recognized that nobody can say with absolute cer¬ 
tainty that these varieties are pure Labrusca and that no Yinifera blood 
is in any way mixed up with them. 
Again, as Y. rotundifolia will hybridize more readily with some 
species than with others, so these varieties, if tainted with blood of 
another species may be either positively or negatively affected in regard 
to their hybridizing qualities. For example, Y. vinifera vines will read¬ 
ily hybridize when Y. rotundifolia pollen is used while Y. labrusca vines 
cannot as readily be hybridized. How Winchell, a Yinifera-Labrusca- 
TEstivalis hybrid, is readily hybridized with Y. rotundifolia pollen; and 
is it not possibly because of the presence in the hybrid of Yinifera blood? 
b. In hybridizing perfect flowered varieties when the species are 
divergent in character, it has been found advisable for the sake of 
economy in time and labor not to lay too much stress on the absolute 
eradication of pollen from the emasculated flowers at the expense of 
possibly injuring their delicate pistils. We have discovered and possess 
evidence which shows that Rotundifolia hybrids are not composed of all 
dominant characters as has long been supposed, but that they are more 
of an intermediate type and an experienced eye can readily pick them 
out from a mixed lot of vines. 
c. When hybridizing different species it is advisable to have at hand 
the freshest pollen obtainable. This may be accomplished in several dif¬ 
ferent ways, chief among which are the following: (1) by forcing late 
blooming vines in an artificially heated glass house, (2) by retarding the 
blooming period of early flowering vines, (3) by diligent search for the 
latest flower clusters on early blooming vines, (4) by forcing, if possible, 
a second crop of flower clusters on a vine, (5) by collecting and storing 
the pollen from early blooming vines for later use. 
d. Some varieties are frequently found that will not readily yield 
positive results in hybridization, while others of the same species may be 
found that will. For example, the variety Scuppernong with us has not 
yielded to the pollen of Y. vinifera while our Oberlin vine has produced 
three berries. Deering (5) mentions a similar experience. 
We (6) have found a vine of our own production which, according to 
our knowledge has not yet been fertilized with pollen from other vines 
