108 THE STORY OP THE PLANTS. 



reminiscences of the five original petals. Indeed, 

 some relations of the primrose, such as the pim- 

 pernel and the woodland loose-strife, have the 

 petals only slightly united at the base, and 

 would hardly be noticed by a casual observer 

 as possessing a tubular corolla. 



There is one marriage custom of the primrose, 

 however, so very interesting that we must not pass 

 it by even in so brief a survey. Most children 

 are aware that we have in our woods two kinds 

 of primroses, which they know respectively as 

 pin-eyed and thrum-eyed. In the pin-eyed 

 form (Fig. 18), only the little round stigma is 

 visible at the top of the pipe, while the stamens, 

 here joined with the corolla-tube, hang out like 

 little bags half-way down the neck of it. In the 

 thrum-eyed form (Fig. 19), on the other hand, 

 only the stamens are visible at the top of the 

 tube, while the stigma, erected on a much 

 shorter style, occupies just the same place in 

 the tube that the stamens occupied in the sister 

 blossom. Now, each primrose plant bears only 

 one form of flower. Therefore, if a bee begins 

 visiting a thrum-eyed form, he will collect pollen 

 on his proboscis at the very base only ; and as 

 long as he goes on visiting thrum-eyed flowers, 

 he can only collect, without getting rid of any 

 grains on the deep-set stigmas. But when he 

 flies away to a pin-eyed blossom, the part of his 

 proboscis which collected pollen before will now 

 be opposite the stigma, and will fertilise it ; 

 while at the same time he will be gathering 

 fresh pollen below, to be rubbed off on the sensi- 

 tive surface of a short- sty led flower in due season. 



