1314 A TEXTBOOK OF THEORETICAL BOTANY 



in Westphalia, Miiller observed that the flowers oi Anethum graveolens were 

 only visited by flies and bees, whereas in Silesia, Loew records that they 

 are chiefly pollinated by beetles. 



Eiion\miiseuropaeuira2iyhQ\.2ikQn as an example of this group (Fig. 1233). 

 The flowers are relatively inconspicuous and comprise four sepals and four 

 small, greenish-white petals which are inserted on the edge of the rect- 

 angular disc. There are four rather squat stamens which stand up at the 



Fig. 1233. — Eiionymiis eiiropaeiis. A, Flowering shoot. B, Flower in 

 early stage with anthers dehiscing. C, Flower in later stage, widely 

 open, with receptive stigmas. 



four corners, betv/een the petals. The ovary rises from the disc in the form 

 of a pyramid the top of which consists of a short, blunt style. The four 

 stamens are remote from the style and the anthers are situated at about 

 the same level as the stigma. Nectar is secreted all round the base of the 

 ovary, between it and the disc, and is therefore accessible to any short- 

 tongued insect. The flow^ers are markedly protandrous. The anthers 

 dehisce extrorsely, while the stigma is still immature. When the stigma is 

 ripe its tip opens out to receive pollen, but closes again as soon as it has done 

 so. Some bushes bear only female flowers, with abortive anthers. Other 

 bushes bear flowers which are structurally hermaphrodite, but which are 

 functionally male and rarely set fruit. Cross-pollination normally occurs 

 as a result of insect visits and self-pollination is almost impossible. Most 

 observers agree that the flowers are chiefly pollinated by dipterous flies, 

 small hymenoptera and beetles, the last being somewhat rare visitors. 



