68 



FLOWERS OF THE WOODS AND COPSES 



flower-stalks. The capsule is 5-valved, with 10 teeth, and many- 

 seeded. 



The Primrose is about 6 in. high in flower. It blooms early in 

 March up to May. It is perennial, and propagated by division of the 

 roots. It is much scarcer than formerly. 



The pollination of the Primrose is familiar from the researches of 

 Knight and Darwin. The flowers secrete honey at the base of the 

 ovary. All the species are dimorphic. In some the stigma extends 



Photo. J. H. Crabtr 



PRIMROSE {Primula vtilgriris, Huds.) 



to the top of the tube, and these are termed long-styled forms, when 

 the stamens lie half-way clown the tube. There are other flowers in 

 which the stamens are inserted near the top of the tube, and where the 

 style is half as long as the tube. The flower is thus heterostylic. The 

 pin-eyed and thrum-eyed forms of children are the corresponding long- 

 and short-styled forms. 



The possession of such differences is of importance to the plant in 

 ensuring cross-pollination. For an insect that visits a long-styled form 

 would thus dust its proboscis with pollen from the stamens half-way 

 down, at a point which, when it visited the short-styled form, would 

 correspond with the position of the stigma in that form, and so lead to 

 crossing of the two types; and in visiting a short-styled form its pro- 

 boscis would be dusted farther from the mouth of the flower, and this 



