
BEHAVIOUR OF PLANTS TOWARD LIGHT 147 
influence of light that they quickly turn if placed near 
a window where there is a one-sided 
illumination. The pot. 
of seedlings shown in 
Fig. 180 was placed near 
a window. In an hour 
they had turned so that 
the cotyledons faced the 
hight coming in from the 
window. Even when 

Fia. 180. Sunflower : 
seedlings lighted Fic. 181. Same seed- 
from above. lings by a window. 
the cotyledons are cut off, the 
stems will turn toward the light, 
as shown in Fig. 182. Any of 
the seedlings which we have 
studied, or others, will turn to 
one side where there is a one- 
sided illumination, but some will 
turn more quickly than others. 
The influences which light has 
on the position of leaves, on the 
growth of the stem, and on the 
symmetrical or one-sided growth 

Fic. 182. The seedlings turn, 
of the branches of ra tree, Can be even though the cotyledons 
are cut away, and stem is 
seen and observed in any place _ cutintwo. 
