4 
Hybridization of Vitis Rotundifolia 
because of insufficient growth in some cases, and death of the vines in 
others. 
These vines have already been described as to their external characters 
by Detjen (3). This paper is limited to the gross anatomy of the 
mature one year canes of the parent vines and their F x generation 
hybrids. Material w T as collected during the early winter of 1921-22, and 
again in the winter of 1922-23. In order to have a uniform basis of 
comparison, only mature one year canes were used. Transverse, radial, 
and tangential sections were cut 25-30 microns thick, from the middle of 
the internode with a table microtome. Combination stains of safranin 
with Delafield’s hematoxylin or with light green were used. Table 2 
lists the different species and varieties of Yitis examined during this 
investigation. 
TABLE 2. SPECIES OF VITIS EXAMINED 
Species 
Variety 
No. of Vines 
Rotundifolia 
Pure species and varieties 
12 
Vinifera 
Malaga 
o 
o 
Bourquinana 
Herbemont 
2 
Labrusca 
Concord 
2 
Labrusca 
Pure species 
3 
Cinerea 
Pure species 
1 
Arizonica 
Pure species 
1 
Californica 
Pure species 
1 
Aestivalis 
Pure species 
5 
Aestivalis 
Norton 
1 
Munsoniana 
Pure species 
1 
Champini 
Pure species 
1 
Bicolor 
Pure species 
1 
Simpsoni 
Pure species 
1 
Doaniana 
Pure species 
] 
Hybrid 
(Labrusca x Aestivalis x Vinifera) Winehell 
O 
Hybrid 
(var. Winehell x V. rotundifolia) 
26 
Hybrid 
(V. vinifera x V. rotundifolia) 
26 
Hybrid 
(V. bourquiniana x V. rotundifolia) 
4 
Hybrid 
[Hybrid (Winehell x V. rotundifolia) x V. 
rotundifolia.] 
1 
VITIS ROTUNDIFOLIA 
Bark. The bark of V. rotundifolia is greenish-grey in color, rather 
smooth, and has numerous lenticels. It is very persistent, never 
shedding on the young wood, and on the very old wood falling off in 
small corky flakes. The stems of the young vines resemble those cf 
maple saplings much more than they do the vines of the Euvitis group. 
Wood. The wood is very hard and compact, the specific gravity 
being about 1.26 with the result that the stems will sink in water. The 
hardness of the wood is especially noticeable in pruning as the stems 
are much more difficult to cut than any Euvitis species. 
Pith. Ihe diameter of the pith column is very small, particularly 
as compared with other species of Yitis, but widens out at the node 
