IMPORTANT RANGE PLAXTS. 57 
duce a small amount of viable seed, while those which have not been 
injured send up their flower stalks early, mature the seed crop before 
killing frosts occur in the autumn, and produce fertile seed. 
The data compiled relative to the life-history performances of the 
different forage species have made possible the adoption of what is 
known as the '" deferred or rotation grazing system." This system 
provides for the deferment of grazing on an allotment imtii the seed 
crop has matured— the size of the area to be protected depending, of 
course, upon the time at which the bulk of the seed crop ripens. 
Subsequent to complete revegetation. the area is grazed relatively 
early, thereby providing for the protection of a similar area elsewhere 
on the allotment without in any way jeopardizing the grazing inter- 
ests or by wasting any part of the annua I forage crop during the time 
required for revegetation. TVhen the entire allotment has been 
thoroughly restocked, each portion, subdivision or camp is restricted 
from grazing but once in everv three or four years, thus alio wins: the 
plants to maintain a maximum vigor and to provide an occasional 
seed crop, which is essential to the maintenance of a permanent 
stand. 
The details essential to revegetation by means of deferred and 
rotation grazing have been given in previous publications. 
85154°— Bull. 54-5—17 S 
