13 



visible, while other flowers of the same species have anthers 

 in the mouth of the corolla- tube, but the style does not reach 

 half-way up ; in these latter plants the pollen grains are 

 larger than in the former, and more seeds are also produced. 

 Experiment showed that short-styled plants produced the 

 full amount of seeds, only when fertilized by pollen from 

 long-styled plants, and this at once pointed to the necessity 

 for insect agency, for both kinds of flowers, though perfect or 

 complete with respect to the apparatus requisite for repro- 

 duction, are almost as dependent on extraneous assistance as 

 if they»were unisexual. Although absolute incapacity for 

 fertilization by the pollen in their own flowers did not take 

 place in Primula, yet in Limim grandiflorum the long-styled 

 form was absolutely sterile when fertilized by its ow^n pollen, 

 but produced perfect seeds by pollen from the short-styled 

 flowers. In connection with this subject, we also have the 

 fact, that in many plants the anthers and stigmas in one 

 flower are not matured at the same time, so as to be capable 

 of acting on each other. If the anthers are mature first the 

 condition is termed j^rotandrous, if the stigmas are, it is called 

 protogynous ; and this state of things points clearly to insect 

 agency being requisite for impregnation. Protandrism is 

 much the most frequent, and Prof. Hildebrand has shown 

 that the whole of the vast group of Compositae come mider 

 this category; the styles elongate before the stigma is 

 matured, and pushing through the tube of ripe anthers, brush 

 ofi" the pollen by means of the hairs with which they are pro- 

 vided, to be again removed by innumerable bees and flies 

 that visit them, and again deposited on stigmas fit for their 

 reception. Could there be a better example of Divine care, 

 than that the means of reproduction should thus be extended 

 over the widest area of time and space in the history of the 

 individual, and of the mutual dependence of one large portion 

 of creation on the services of another ? 



