13 



Time of Opeaitig of Flowers. It is well known that tem- 

 perture and moisture greatly inflnence the f)pening of ftow- 

 ers. Rains and lows temperature may retard the opening 



FIG. 5. 



Fig. 5. Tall meadow oat grass, {Arrhenatherum elativs). Wind pollinated, 



showing how anthers open and the long plumose stigmas protruded. 1, Closed 



anther. 2, An opened anther. 3, Parts of the pistil separated. 4, The effect 



wind has on the flowers. (After Kernep von Marilaun.) 



not onlj' hours, but days. Dry air and a high temperature 

 also retards opening. The flowers of grasses open early in 



