Hybridization of Yitis Rotundifolia 
15 
in the hybrids of V. rotundifolia with V. vinifera var. Malaga, and with 
Yitis hybrid var. Winchell has not, been determined. The difference 
between V. rotundifolia and each of these is apparently about the same 
as far as actual characters are concerned. Whether the genetical dif¬ 
ference is greater in case of var. Winchell crosses due possibly to its 
own hybrid nature, is still to be investigated. Unfortunately, indi¬ 
viduals of crosses between V. rotundifolia and each of the species rep¬ 
resented in the pedigree of Winchell cannot at this time be examined. 
A study of V. labrusca and T 7 . aestivalis has given no additional in¬ 
formation. 
This study ot the anatomy of the stems of Yitis species probably 
explains the difficulty of rooting Muscadine cuttings, and grafting V. 
vinifera on Muscadinia species roots. It may be possible to develop a 
hybrid root resistant to phylloxera and on which the V. vinifera may 
be easily grafted. 
SUMMARY 
The stems of the subgenera of Yitis, namely, Muscadinia and Euvitis, 
have distinctly different anatomical characters. 
These characters may be summarized as follows: 
Character 
Muscadinia 
Euvitis 
Bark 
persistent 
shedding 
Uenticels 
present 
absent 
large, of thin-walled cells 
Pith 
small, of thick-walled cells_ 
Diaphragm 
Wood fillers 
absent at node 
small diameter, thick-walled. 
present at node 
larger, thin-walled 
Phloem section_ 
triangular 
square 
Hard bast 
outlines soft radially 
in alternate layers with 
Sclerenchyma 
small bundle of round thick- 
soft fibers 
large bundle of angular 
fibers 
walled fibers 
fibers 
Rays in inter- 
widen by cell increase 
continue the same width 
vascular region. 
Phelloderm 
present 
absent 
Pliellogen 
immediately under epidermis. 
just outside of phloem 
Sp. gravity of 
greater than water 
less than water 
fresh cut wood- 
In crosses between the species of these subgenera, the hybrids inherit 
the anatomical characters as well as the morphological characters, and 
just as strikingly as the external characters usually studied. 
These characters in the hybrids were intermediate resembling either 
parent with varying degree, but with possibly greater resemblance to 
the T 7 . rotundifolia parent. 
In the hybrids with var. Winchell there was less resemblance to the 
T 7 . rotundifolia parent than in the I 7 , vinifera^ hybrids. 
The degree of the expression of the intermediate condition was about 
uniform in all the characters of any one vine. That is, a vine with 
