74 



BOTANY OF CROP PLANTS 



(Fig. 27), and the entire mass of- branches is the "stool." 

 Common cereals, such as wheat and oats, invariably pro- 

 duce a number of tiUers, sometimes as many as 50. The 

 tillers from the primary culm may produce tillers (lateral 

 branches) and these in turn other tillers, so that under favor- 

 able conditions several dozen culms may result from a single 

 seed. As the internodes are much shortened, the branches 



Fig. 27.- 



'-tertiary stem 

 -scale kaf 

 'secondary siem 

 'primary Stem 



=crown roots 



—^rain remains 

 .J^sprmarv roots 



-Diagrammatic representation of tillering in cereals. 

 {After Schindler.) 



appear to come out at one point. In the wheat plant, two 

 or three weeks old, three or four buds may be found, one in 

 the axil of each leaf. Tillering results from the outgrowth 

 of these lateral buds. 



Tillering activity varies with the species, the individual, 

 and environmental conditions. In general, winter grains 

 tiller more than summer ones. It is dependent especially 

 upon the depth of seeding. There seems to be an optimum 

 depth, which varies with the sort of grass. The average 

 depth of the tillering node in cereals is about i to 2 centi- 



