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 
e. 
Photo. J. H. Crabtree 
PRIMROSE (Primula vulgaris, Huds.) 
to the top of the tube, and these are termed long-styled forms, when 
the stamens lie half-way down 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 
