58 VARIETAL CHARACTERS OF INDIAN WHEATS. 
dividing the varieties lies in the fact that in the south there are 
many more intermediate forms to be found than is the case with 
the German wheats. He considers this is probably due to the 
fact that in certain countries the sowings are extraordinarily 
mixed—wheats from Valencia gave on sowing a large number of 
varieties. In such cases Koernicke considered that it is easier for 
crosses to occur and the limits of the groups to be lost. 
Fruwirth' brings together most of the recorded examples of 
natural crossing in wheat. The possibility of cross-fertilisation is 
supposed to have been proved for T. sativum, Vill., by an experi- 
ment of Rimpau in which 59 per cent. of castrated flowers freely 
growing in a wheat field set seed and by a similar experiment of 
von Liebenberg’s in which 20 per cent. of flowers in the same 
manner set seed. As mentioned above, Garton in a similar ex- 
periment in England obtained no setting. Rimpau observed the 
occurrence of spontaneous bastards when different kinds were 
grown next to next. He cultivated 60 kinds of 7. vulgare for 15 
years and found 17 cases in which one could assume spontaneous 
crossing. Hansen at Lyngby and Nilsson at Svaléf are of opinion 
that in warm good weather forms cross with each other which 
are generally considered only to be self-fertilised, and that crossing 
between common wheats and spelts occurs under such circum 
stances. Fruwirth states that at Hohenheim he also noticed 
similar results and also crossing between forms of 7. satvwvwum and 
spelta. 
In the United States, Carleton’ considers that natural cross- 
ing sometimes occurs, and states ‘‘ In a majority of the instances 
above described the circumstances too are such that one cannot 
escape the thought that the abnormal heads found in the fields 
were the results of natural crosses.’’ In Canada, Saunders’ has 
described a case of spontaneous crossing in the field between Red 
Fife (female) and Rio Grande (male). 
1 Fruwirth, lc. 
* Carleton, Bull, 24, VU, 8, Department of Agriculture, Div, of Veg. Phy. & Path.. 1900 
8 Saunders, Bull, 57, Canadian Dept. of Agr, Oct. 1907. 
