8o GERANIUM. [CHAP. 



together (b) t so that the stigmatic surfaces are not ex- 

 posed. Nor do they separate (Fig. 42), or become 

 susceptible of fertilisation, until after the anthers have 

 all shed their pollen. The flower, in fact, passes 

 through three distinct stages : first, the five outer 

 stamens open, and shed their pollen ; then the five 

 inner ones ; and lastly, after the pollen is all shed, 

 the stigmatic surfaces expand and attain maturity. 

 The flower therefore cannot fertilise itself. 



On the other hand, in the smaller species of 

 Geranium the stigmas come to maturity before the 

 stamens have shed all their pollen ; hence the visits 

 of insects are not so necessary, and hence, probably, 

 the smaller size of their flowers. (See ante p. 48.) 



There is also another difference, to which I will call 

 attention. G. Robertianum does not possess the 

 fringes of hairs by which the honey is in G. sylvaticitm 

 protected against the access of rain ; on the contrary, 

 the petals are entirely glabrous. This difference is 

 apparently connected with the form of the flower, 

 which is less open than is the case with G. sylvaticum 

 On the contrary, it forms a distinct tube, the entrance 

 to which is sufficiently protected against rain by the 

 stamens and pistil. 



The smaller flowered species moreover offer remark- 

 able differences among themselves. Thus G. molle 

 and G.pusillum are at first sight very similar, and, as 

 Bentham observes, are no doubt sometimes confused ; 

 yet they differ remarkably. When G. molle first 

 opens, the pistil is immature, and the stigmatic 

 surfaces are closely appressed. The outer anthers 

 then begin to open one after the other, so that the 



