42 HOW TO MAKE SCHOOL GARDENS 
kept from mice, they will keep several 
years. 
Wheat is a grass closely related to 
barley and rye. It has a dense four- 
sided spike, and grains longitudinally 
furrowed on one side, turgid on the other. 
Some varieties have awns or beards ; 
one being planted in autumn, the other 
in spring. From it comes the principal 
breadstuff of the civilized world. A grain 
in weight was originally derived from a 
plump grain of wheat. 
Wheat was introduced into China 2,700 
B. C. 
Oats differ from other grains in mode 
of flowering, having panicles instead of 
spikes. Used in human food and much 
used for horses. Often cut “in the milk” 
for a fodder crop. 
