Bui. 1450, U. S. Dept. of Agriculture 
Plate 12 
A Study in Effect of Light 
Two timothy plants, propagated vegetatively from the same original plant, which were grown 
under different periods of daily illumination for a period of slightly over three months. The 
plant at the right was in the daylight 7 hours each day, and the one at the left received natural 
or artificial light 16.5 hours each day. None of the stems became elongated on the plant grown 
under the shorter day, while on the plant grown under the longer day the internodes of the 
culm became elongated and on four of the shoots heads were produced 
