CHAPTER V. 



SPECIAL ADAPTATIONS. 



Members of this family shows various 

 RaMttticttiaceae. jjdaptations to pollination. Some of the 

 flowers are very conspicuous and are adapted to long- 

 tongued insicts, as species of columbine, ( Aguilegia), Del- 

 phiniwin and Aconitum- Buttercups, with shallow and un- 

 protected nectar, are adapted to a wide range of visitors, 

 Hymenoptera, Diptera, etc. 



Clematis Virginiana, L. The flowers are borne in 

 large conspicuous clusters, dioecious. The nectar is easily 

 accessible and hence numerous small insects are attracted. 

 Robertson stated that three-fifths of the visitors are flies. 

 Some of the species of Clematis, like C. Jachmanii, have 

 very conspicuous flowers. The European C. recta L- is 

 proterandrous and without nectar. In C- integrifolia, the 

 inner stamens secrete nectar. The CleniMtis Pitcheriii 

 Torr. & Gray, which flowers much earlier, is adapted to 

 bumble bees. In this species the filaments which secrete the 

 nectar are closely approximated so that bees are admitted by 

 a small opening. Robertson has made an interesting com- 

 parison of the insects visiting Isopyrum biternatum Torr. 

 & Gray, and Clematis Virginiana, L. The former, 

 which blooms in early spring, is visited by 31 Hymenoptera, 

 the latter by 9; bees and Syrphidae are less abundant on the 

 latter. It is visited also by 10 Tachinidae, 7 Muscidae and 

 11 other Diptera; the former by 4 of these. 



