THE FERTILISATION OF FLOWERS. 323 



growing mingled together, pollen from the long-stamened form, 

 adheres round the base of the object, and is left with certainty on 

 the stigma of the long-styled form ; whilst pollen from the short 

 stamens of the long-styled form adheres a little way above the 

 extremity of the object, and some is generally left-on the stigma^ of 

 the other form." Mr. Darwin is also careful to note that " self-fertilisa- 

 tion " must occasionally occur in these flowers, through " an insect, in 

 withdrawing its proboscis from the corolla of the long-styled form," 

 leaving pollen from the flower on that flower's own stigma. Such a 

 result will occur most frequently in the case of the short-styled 

 flowers, as may be experimentally demonstrated, and small insects, 

 such as those belonging to the genus Thrips, wandering aimlessly 

 about within the flower may likewise be the means of inducing self- 

 fertilisation. But, as if in anticipation of such defeat of her clear 

 intent and purpose, we find a very significant observation brought to 

 light in the fact that even if a flower's own pollen be placed on its 

 pistil, cross-fertilisation may yet take place, inasmuch as pollen from 

 a different form of flower seems to be capable of obliterating the 

 effect of the flower's own pollen, " even," adds Mr. Darwin, " when 

 this has been placed on the stigma a considerable time before." An 

 experiment of very crucial nature supplies an instance of the pre- 

 potent effect of foreign pollen over a flower's own. On the stigma 

 of a long-styled cowslip Mr. Darwin placed " plenty of pollen from 

 the same plant." After a lapse of twenty-four hours he added pollen 

 " from a short-styled dark-red polyanthus, which is a variety of the 

 cowslip. From the flowers thus treated thirty seedlings were raised, 

 and all these, without exception, bore reddish flowers ; so that the 

 effect of pollen from the same form, though placed on the stigmas 

 twenty-four hours previously, was quite destroyed by that of pollen 

 from a plant belonging to the other form." 



The philosophy of primrose-existence can hardly be said to be in 

 any sense comprehended through the mere knowledge of the con- 

 trivances which exist' in that flower for the prevention of self-fertilisa- 

 tion and the favouring of the opposite process. On the contrary, the 

 philosophy which carries with it the understanding and appreciation 

 of the system and order of nature is only discernible when, firstly, 

 we step forth more fully " into the light of things," and when, 

 secondly, we discover, from such wider views of flower-life, the 

 advantages gained and the ends served b^y the processes under con- 

 sideration. Hence, for the present, we may turn with profit from the 

 polity of a primrose to discuss some analogous feature in that wider 

 realm of flowers to which the primrose and its kind may fitly intro- 

 duce us. After such survey we may, with additional likelihood of 

 arriving at just conclusions respecting the philosophy of plant-life, 

 return to the Primula and its lessons once more. 



