140 ANGIOSPERMAEDICOTYLEDONES 



can reach the nectar (Fig. 38). The flowers are, in fact, chiefly visited by flies. It 

 has yet to be determined whether automatic self-pollination can take place should 

 insect-visits fail. 



Lindman observed on the Dovrefjeld flowers exhibiting a transition to cleistogamy, 

 in addition to the chasmogamous ones, which resemble those of the Alps. In these 

 the lateral petals, and sometimes even the anterior ones, are greatly reduced. In 

 individual flowers the style may be very short, so that the pollen-surrounded stigma 

 occupies the position which is usual in cases of cleistogamy. 



Visitors. Herm. Miiller observed the following in the Alps. (a) Flies, par- 

 ticularly Syrphidae 7 species which sucked from above, and regularly effected 

 cross-pollination ; the larger Muscidae behaved similarly. (&) Short-tongued bees 

 Halictus cylindricus F. which first attempted to suck from below, but quickly 

 learned the proper way of securing nectar from above, (c) A few Lepidoptera, skg. 



MacLeod noticed 2 Muscids in the Pyrenees (' Pyreneenbl.,' pp. 398-9). 



351. V. lutea Sm. 



Visitors. Willis and Burkill ('Fls. and Insects in Gt. Britain,' Part 1) observed 

 the following Muscids in Central Wales : 1. Anthomyia sp. ; 2. Hylemyia lasciva 

 Zett., skg. ; 3. Siphona geniculata Deg., skg. 



Wittrock noticed near Stockholm on the variety grandiflora Vill. humble-bees 

 and Lepidoptera. 



352. V. sepincola Kern. Kerner states that the flowers of this species are 

 chasmogamous in sunny places, but cleistogamous in shady woods. Both hemi- 

 cleistogamous and eucleistogamous flowers occur, according to Calloni (Bui. Soc. bot., 

 Geneve, v, 1889). 



353. V. sciaphila Koch. Calloni states that in this species there are hemi- 

 cleistogamous or eucleistogamous flowers, in addition to the chasmogamous ones 

 which appear in spring. 



354* V. stagnina Kit. Corry says that this species possesses cleistogamous 

 flowers. 



355. V. montana L. Linnaeus long ago observed cleistogamous flowers in 

 this species. 



356. V. elatior L., and 357. V. lancifolia L. Both these species bear 

 cleistogamous flowers, according to Daniel Miiller (Bot. Ztg., Leipzig, xxv, 1867). 



358. V. bicolor L. Hermann Miiller ('Fertilisation,' p. 121) states that there 

 are cleistogamous flowers in this species. 



359* V. mirabilis L. There are cleistogamous flowers in this species, according 

 to Dillenius. 



360. V. palustris L. (Knuth, Bl. u. Insekt. a. d. nordfr. Ins.,' p. 33.) The 

 small flowers are of a bright lilac colour, and the lower petal is streaked with dark 

 violet. 



Visitors. In Dumfriesshire a Muscid has been observed (Scott-Elliot, ' Flora of 

 Dumfriesshire,' p. 20). 



361. V. cornuta L. The flower exhales a strong odour at night, and, according 

 to Hart (' Fertlsn. of Viola tricolor and V. cornuta '), is adapted for pollination by 

 moths. The spur is longer than the corolla. 



