380 



HUTCHINSON'S POPULAR BOTANY 



like corkscrews. This is the insect's last chance, and now, should no fertili- 

 zation have taken place, the flower enters upon its third and final stage. 

 For this, it assumes a completely pendent position (fig. 459). While anthers 

 and stigma draw together, the branches of the latter open and present their 

 stigmatic surfaces, and, finally, the pollen falls upon them. On the whole, it 

 is a wonderful instance of the parts of a flower co-operafcing to a given end. 

 From what has been said it will be abundantly clear that though the 

 pollen of a bisexual flower may effect the pollination of that flower, such a 

 result is by no means inevitable ; indeed, as a matter of fact, a very large 

 number of bisexual flowers are almost always cross-pollinated ; and Darwin 

 has shown pretty conclusively that in many plants cross-fertilization has a 

 distinct advantage over self-fertilization at least, for some generations 

 inasmuch as the flowers thus crossed produce more numerous seeds and 

 healthier seedlings. 



This is not the place to discuss the much-debated question whether, in 

 the long run, plants are gainers by cross-fertilization. It is a point upon 

 which botanists are still divided. One eminent observer, Professor George 

 Henslow, says emphatically that habitually self -fertilized plants are the most 



prolific, and that our previous 

 ideas, based upon Darwin's 

 experiments and theories, are 

 all wrong, and must be re- 

 versed. " The most conspicu- 

 ous flowers and regularly (if 

 at all) fertilized by insects 

 are not," he asserts in his The 

 Making of Floivers, " the best 

 off; but they cannot help them- 

 selves. The responsive power 

 within them is automatic, so to 

 say, and not volitional. What- 



;J^| J ever an insect does to them, 



^^^ they must yield to it, and grow 



f in adaptation to it, but while 



/ they are thus being stimulated 



m to become what ive may choose 



m to call finer flowers and hand- 



somer plants with larger 



^^ leaves and so on, yet all this 



is secured at a sacrifice of 

 fertility." He contends that 



though Darwin proved that 

 FIG. 468. INDIAN CROCUS (Ccelogyne lagenarw). ^ . 



intercrossing is a stimulating 



A beautiful Orchid whose lip is veined and striped to provide . a 

 honey-guides for insects. See also fig. 470. pTOCeSS at least, for a time 



