260 



MINNESOTA BOTANICAL STUDIES 



nent color contrasts against the dull or somber gray of the grama- 

 buffalo-grass setting. Pronounced color changes mark the ephem- 

 eral life-history of these communities. The initial green is grad- 

 ually lost with the decomposition of chlorophyll and the development 



Fig. IS. Grama grass, Bouteloua oligostachya. Typical plant, 

 a; empty glumes, b; perfect and imperfect flowers, 

 c. (From Shantz.) 



of a bright, clear straw color. Only a few days later the same 

 plants have changed their color to a light brown, which finally, after 

 a few more days, gives way to a most beautiful reddish-brown. 

 These changes are brought about more rapidly during a dry season 



