4 BULLETIN 34, U. S. DEPARTMENT OF AGRICULTURE. 



there must be a constant supply of the necessary food material from 

 the soil. Moisture, which is supplied by the minute root hairs, is 

 continuously being given off as vapor by the pores of the leaves and 

 stems, and when the balance between the moisture taken up by the 

 roots and that given off by the foliage is disturbed the plant wilts, 

 and if the disturbance continues finally dies. Anything which de- 

 stroys the delicate root hairs, therefore, decreases the capacity of the 

 plant to absorb moisture and is at once reflected in a decline in health 

 and vigor of the herbage. 



On the other hand, proper development of the root system is de- 

 pendent upon a supply of food furnished by the part of the plant 

 above ground, and so when the plant loses its green herbage the 

 roots suffer accordingly. If the foliage is continually removed during 

 the season when growth is most active the root system is greatly en- 

 feebled and if the practice is continued is at last starved beyond re- 

 covery. 



PRODUCTION OF FLOWER STALKS AND SEED CROPS. 



If depleted range lands are to be revegetated, the forage must be 

 allowed to produce a fertile seed crop. The vigor of the vegetation 

 greatly influences, in fact, sometimes determines (1) the time of 

 flower-stalk production; (2) the number of flower stalks sent up; 

 (3) the time of seed maturity and the size of the seed crop; and (4) 

 the fertility of the seed. 



The time of flower-stalk production depends chiefly upon three 

 factors : The season, whether early or late ; the character of the soil 

 or physical conditions; and the vigor of the plants or herbage pro- 

 duction. The beginning of the season in mountain lands may vary 

 in a given locality as much as 10 da}^s, and this wide variation of 

 the time when growth begins necessarily brings about a correspond- 

 ing variation in the time of flower-stalk production. 



The influence which the vigor of the vegetation has upon the time 

 of flower-stalk production and the number of flower stalks is illus- 

 trated by the following experiment : An area which had been severely 

 overgrazed was fenced against stock, and for five years, while the 

 vegetation gradually recovered, observations were made to determine 

 any changes in the number of flower stalks produced and the time of 

 their production. During the first year of protection no flower stalks 

 were seen until July 25, and it was not until 41 days later that all 

 the stalks had been produced. The following season the stalks began 

 to shoot up as early as July 10, and all had been produced 30 days 

 after the appearance of the earliest ones, a decrease in time of nearly 

 27 per cent after one year's protection. In subsequent seasons the 

 time required for flower-stalk production was only slightly less than 

 that during the second season of protection. Early production of 



