Robertson — Floicers and Insects. 



173 



higher bees. The following table gives the results of obser- 

 vations which have been made in this line : — 



Miiller says that cross-pollination is insured in case of insect 

 visits, but self-pollination can hardly occur in their absence. 

 Henslow (7) regards spontaneous self-pollination as probable, 

 but admits that it is less likely when the flowers are pendulous. 

 This, however, according to Miiller, is their normal position. 



From observations of Delpino (14) it appears that nectar 

 is secreted by the corolla and not by the swollen base of 

 the style, as claimed by Miiller. In this Loew (21) states 

 that Delpino is anticipated by Kurr (1), but Kurr's observa- 

 tions were on S. vulgaris. 



Stmphoricarpos vulgaris Michx. — S. symphoricarpos 

 (L.) Mac M. — In Patterson's Catalogue this species is not 

 credited to Illinois. It agrees in a general way with Midler's 

 account of S. racemosus. The flowers are collected in 

 axillary clusters. They are commonly pendulous, but vary 

 from that position to erect. The corolla tube is about 2 mm. 

 long and expands at the throat about 3 or 4 mm. It is green- 

 ish-white with a trace of rose color. The nectar is concealed 

 by hairs arising from the inner wall of the corolla near the 

 insertion of the filaments. The stamens occupy a position near 

 the corolla wall and have introrse anthers which surpass the 

 stigma. The flowers are homogamous. Wasps comiug with 

 their noses covered with pollen are more likely to effect cross- 



