24 VARIETAL CHARACTERS OF INDIAN WHEATS. 
species which can be differentiated in properly developed single 
individuals by definite, inherited and easily distinguishable charac- 
ters, such as the presence or absence of the awns, smooth or felted 
chaff, colour of the glumes and grains. Our varieties are therefore 
the botanical units of the species and sub-species and represent the 
lowest limit to which wheats can be divided in the laboratory with 
precision. Each variety, however, may comprise several agricul- 
turally distinct types. We have divided the varieties where neces- 
sary into types by means of the field characters, such as length and 
strength of straw, earliness or lateness, tone of colour of chaff and 
straw, erectness of the ear, and susceptibility torust. The types 
represent the agricultural units of a variety in asimilar manner as 
the varieties are the botanical units of the species or sub-species. The 
agricultural types are just as constant as the botanical varieties, but 
are not so readily distinguished except in the field. To determine 
the types it is necessary to grow them in pure culture for several 
years under uniform conditions. We have in our study of the 
Punjab wheats carried the classification down to the type. Our 
types are practically synonymous with the ‘‘ Sorten’’ of Fruwirth 
and Koernicke. In more than one case the same botanical variety 
contained valuable and almost useless types. Wehave found it 
best to distinguish the types not by one character alone but by 
the sum of their field characters. 
As regards the system of classification in the cultivated 
wheats, three have been proposed—those of Koernicke,’ 
Eriksson’ and Vilmorin. It has beenalready pointed out that the 
system of Eriksson depends on the density of the spikelets and is 
unsuitable foruse in India. Vilmorin has not sufficiently distin- 
guished between the types, while Koernicke in Die Arten and 
Varietaten des Getrerdes, only considers the botanical varieties. 
Koernicke’s classification has been extended by Werner* in 
Die Sorten und der Anbau des Getreides, but he has only 
Koernicke, |, ¢. 
1 
2 Eriksson, |. c. 
4 Vilmorin, |. c. 
4 
Werner, Die Sorten und der Anbau des Getreides, Bertin, 1885. 
