RUBUS STRIGOSUS. 



99 



Experiments. — In the first case all three plants were rooted in position, 

 affording a test of natural competition. In the others, Rubus strigosus 

 was the standard and its competitors were arranged in bouquets or vials. 



Summary. — The total number of visitors to Rubus was 232, in contrast 

 with 62 to all its competitors, though the raspberry was undoubtedly favored 

 by being the plant in each case. With the flowers in vials, Geranium and 

 Chamaenerium exerted no competition whatever and that of Cleome was 

 negligible. Mertensia approached Rubus in attractiveness and Frasera 

 apparently exceeded it, as suggested by the relatively greater number of 

 visits per insect. This was especially true of the honey-bee. 



RUBUS STRIGOSUS AND TWO OR MORE COMPETITORS. 



Comparison. — The flowers of the two species of Pentstemon are much 

 larger than those of the raspberry, but they contain much less pollen and 



