VIOLARIEAE 



141 



Visitors. — Hart observed an owlet-moth — CucuUia umbratica L. — a butterfly — 

 Hipparchia janira L. — and humble-bees. 



Wittrock noticed Bombus subterraneus L. and several butterflies near Stockholm. 



362. V. pinnata L. (Herm. MuUer, ' Alpenblumen,' p. 151.) — The lower lip 

 possesses no hairs for the reception of the pollen which falls from the cone of anthers. 

 The proboscis of an insect when thrust into the spur is, therefore, not covered with 

 pollen from below, but from above, so that the lower margin of the stigma is pollinated 

 and crossing is effected. Self-pollination is prevented by a pronounced broadening 

 of the rim of the stigma (see Fig. 39). Linnaeus long ago observed cleistogamous 

 flowers. 



Visitors. — These are probably bees. 



Fig. 39. Viola pinnaia, Z.. (after Herm. Miiller). A. Front view of flower. B. Section through 

 flower. C. Reproductive organs. D. Pistil seen from the side. E. Front view of style and stigma. 

 {A and .ff x 3J ; C—E x 7.) 



363. V. arenaria DC. (Herm. Miiller, 'Alpenblumen,' p. 152.) — The flower 

 mechanism agrees with that of the last species. The proboscis of an insect is dusted 

 with pollen from above, and self-pollination is prevented. The margin of the stigma 

 is not expanded, but beset with stiff', projecting hairs (see Fig. 40). 



At Kongsvold on the Dovrefjeld Lindman found that the flowers were cleisto- 

 gamous during the first three weeks of July, and set fruits. Kerner observed in the 

 Tyrol cleistogamous flowers on the prostrate runners, besides the chasmogamous ones. 



Visitors. — Herm. Miiller observed butterflies (Vanessa). 



364. V. tricolor L. (Sprengel, 'Entd. Geh.,' pp. 386-400; Hildebrand, 'Die 

 Geschlechtsvert. b. d. Pfl.'; Herm. MuUer, 'Fertilisation,' pp. 11 7-1 8, ' Weit. Beob.,' 

 II, pp. 206-9; MacLeod, Bot. Jaarb. Dodonaea, Ghent, vi, 1894, pp. 215-20; 

 Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 33, 150; Kirchner, 'Flora v. Stuttgart,' 

 p. 320.) — Hermann MuUer says that to get at the nectar insects must introduce their 

 proboscis immediately below the spheroidal stigmatic head, and so on into the spur. 



