Blossom and Seed 17 r 



The dog-violet, on the other hand, as it does not resort 

 to this device, is quite seedless, unless pollen be brought 

 to it ; and other plants are much worse off, and can never 

 set seed at all in this country, being unable to make use 

 of their own pollen, and not finding here the messengers 

 which, in their native land, bring them pollen from other 

 plants. The greater periwinkle is one of these, and never 

 has seed. 



As has been mentioned, some blossoms have pistils so 

 much longer than the stamens that it seems impossible for 

 the pollen of the one to reach the tip of the former. This 

 is the case with the colchicum, whose mauve-colored blos- 

 soms are much like those of the crocus. But when the 

 pollen is ripe and the anthers have burst some of the dust 

 is rubbed off upon the inside of the petals when the flower 

 closes, as it does every night, several times in succession. 

 Meanwhile the petals lengthen so much, that when the 

 blossom closes for the last tim.e, the first spots of pollen 

 are brought up to a level with the tip of the pistil and are 

 pressed against it, with the result that some of the grains 

 adhere to the sticky surface and soon begm to grow, at 

 the rate of something more than an inch in an hour. 



In the case of the colchicum, the ovules are a very 

 long way from the pistil-tip — as much as thirteen inches — 

 but they are reached in about twelve hours. This takes 

 place at latest at the beginning of November; but for 

 some reason, perhaps because it needs warmth, the germ 

 or embryo does not begin to form in the ovules until the 

 following May. 



The ovules of the American oak wait almost a year 

 after the entrance of the pollen-tube before they begin to 

 develop, and then take another year to ripen. 



