176 Ikeno . — On Hybridization of some Species of Salix . II. 
The result of the same hybridization done in 1911 was quite different 
from that of 1910. It has given rise to almost fifty plants which were not 
hybrids, as was expected, but midtinervis , i. e. identical with the mother- 
plant ; all were found to be female. 
II. Formation of Hybrids. 
1. General and F 1 Generation . 
Though, as stated above, multinervis x gracilistyla has always given 
rise to a certain number of progeny, its reciprocal cross, i. e. gracilistyla x 
multinervis , was unsuccessful even by repeated trials (done in 191a and 
1918), and I stated in my former paper that this hybridization is 
wellnigh impossible. 1 This conclusion was, however, rather hasty. In 
1919 I once more tried this operation, and was much astonished to 
see that this time I obtained success, though scanty. I have pollinated 
many ears, but only three have given some seedlings and I have obtained 
twenty-one hybrids in all. Of these four have died down, and I have now 
seventeen planted in my garden ; they have not flowered yet, except two, each 
of which has borne G-type female catkins. So far as I am able to judge by 
their leaves, the remaining fifteen are certainly hybrids exactly similar to 
those ex midtinervis x gracilistyla. The definite classification of all of 
them according to the nature of their catkins is thus still impossible, and 
they are consequently of not much use in my present experiment. I wish 
merely to point out the fact that gracilistyla x midtinervis may be success- 
ful, though very rarely. 
From midtinervis x gracilistyla carried on in 1910 I got only four- 
teen hybrids. As this number is very small I repeated the same 
hybridization in 1918, and obtained many more offspring. Though seven 
of them have not yet produced flowers, those with flowers may be classified 
as follows : 
.Table I. 
No. of 
Cross. 
Progeny. 
No. of 
Cross. 
Progeny. 
G-type. M-type. 
GM. 
MM. 
Totals. 
G-type. M-type. GM. 
MM. 
Totals. 
1 
1 
1 
1 6 
1 
1 
2 
5 
5 
17 
1 
1 
4 
1 1 
2 
18 
1 
1 
5 
1 
1 
J 9 
1 
1 
6 
1 1 
2 
20 
2 
2 
7 
8 
8 
22 
1 
1 
8 
4 
4 
23 
1 
1 
10 
3 2 
5 
26 
4 
1 
5 
1 1 
14 
1 
15 
28 
4 3 
... 
7 
13 
5 1 
6 
29 
... 
1 
1 
14 
1 
1 
3 ° 
1 1 
2 
Totals 
59 11 1 
2 
73 
