ONAGRARIEAE 



45i 



which projects rather further from the flower, and bears a terminal capitate stigma. 

 These three organs serve as alighting-rods, by which an insect must support itself 

 while getting at the nectar, which is secreted in the base of the flower by a ring 

 surrounding the beginning of the style. As the latter is somewhat lower and 

 longer than the stamens, insect visitors mostly alight upon it, and will effect crossing 

 if they are dusted with pollen from another flower. They apply this to the bilobed 

 stigma with the under- side of their body. The visitor next proceeds to get nearer 

 the nectar, using its fore-legs to seize the stamens by their thin easily yielding 

 bases, and pulling them inwards and downwards. The dehiscing anthers are thus 

 brought into contact with the under-side of the 

 body, dusting it anew with pollen. 



An insect not infrequently alights upon 

 one of the two stamens. As this bends 

 downwards from the weight, its base and 

 the style are at once seized by the fore- 

 legs. In this way the stigma is usually 

 brought into contact with the under-side 

 of the visitor, and crossing results if a visit 

 has previously been paid to another flower, 

 for the stigma and anther touch opposite 

 sides of the body. 



If insect-visits fail, automatic self-pol- 

 lination is usually excluded, for it but 

 rarely happens that the anthers and stigma 

 come into direct contact when the flower 

 fades. 



Visitors. These are exclusively Diptera, 

 especially Syrphids. I observed the following, 

 all skg. and po-dvg. 



(a) Muscidae : 1. Lucilia cornicina F. ; 2. Musca domestica L. ; 3. Scatophaga 

 stercoraria Z. (d) Syrphidae : 4. Ascia podagrica F. ; 5. Eristalis nemorum Z. ; 

 6. Melanostoma mellina Z. ; 7. Syrphus sp. 



Herm. Miiller gives a similar list. 



(a) Muscidae: 1. Anthomyia sp. ; 2. Musca domestica Z. {b) Syrphidae: 3. 

 Ascia podagrica F. ; 4. Bacha elongata F. ; 5. Melanostoma mellina Z. 



MacLeod saw an Andrena and a hover-fly in Flanders (Bot. Jaarb. Dodonaea, 

 Ghent, vi, 1894, p. 299). 



In Dumfriesshire, a hover-fly was recorded (Scott-Elliot, 'Flora of Dumfries- 

 shire,' p. 67). 



1068. C. alpina L. The flower mechanism is the same as that of the last 

 species. Kerner states that automatic self-pollination takes place towards the end 

 of anthesis, one or both anthers being applied to the stigma. 



Visitors. These are again chiefly hover-flies, which behave as described for 

 the last species. I observed the medium-sized forms Melanostoma mellina Z. and 

 Eristalis sp. 



GSf 2 



Fig. 153. Circaea lutetiana, L. (after Hertn. 

 Miiller). Flower seen obliquely from above, a, 

 ovary ; d, sepal ; c, petal ; d, stamen ; e, stigma. 



