On Floivers and Insects. 



Hoary Willow Herb (fig. 34) has small solitary 

 flowers, and is seldom visited by insects. Now in 

 the former species their visits are necessary, because 

 the stamens ripen and shed their pollen before the 

 pistil, so that the flower is consequently incapable 

 of fertilising itself. In the latter species, on the 

 contrary, the stamens and pistil come to maturity at 

 the same time. 



3. Let us take another case, that of certain Gera- 



Fig. 34. HOARY WILLOW HERB (Efilobium parviforum). 



niums. In the Meadow Geranium (fig. 35), which 

 has a very large flower, all the stamens open, shed 

 their pollen, and wither away, before the pistil comes 

 to maturity. The flower cannot, therefore, fertilise 

 itself, and depends entirely on the visits of insects 

 for the transference of the pollen. In the Moun- 

 tain Geranium, where the flower is not quite so 

 large, all the stamens ripen before the stigma, but 

 the interval is shorter, and the stigma is mature 

 before all the anthers have shed their pollen. It is, 



