PENTSTEMON. 



Ill 



available in each flower for a much longer period. Both Aconitum colum- 

 bianum and Delphinium scopulorum afford a striking contrast to the fireweed 

 in the form and color of the flower. The blue or purple color and the great 

 abundance of pollen would seem to make them more attractive, but this is 

 offset by the more constant flow of nectar in Chamaenerium. Frasera 

 speciosa is similar to the latter in the form and size of the flower, but the 

 corolla is dull green. It would seem to be greatly handicapped by the 

 color and the small number of stamens, but the nectar is abundant and 

 apparently very palatable, a fact that more than compensates for the 

 larger size, brighter color and more abundant pollen of Aquilegia coerulea 

 (plates 2, 7, 8, and 10). 



Table 77. — Plant and bouquet competition of several species. 



Experiments. — In table 78 the first record is one of natural competition 

 between fireweed and geranium, the next two are experiments in which 

 the former was the standard plant and the last is an isolated one with 

 Frasera, a flower of similar form but very different color. 



Summary. — Chamaenerium proved many times more attractive than 

 either Aconitum or Delphinium; it received fewer visitors than Geranium, 

 though this was only exceptionally true, and was due to the absence of 

 Bombus. The usual efficiency of the columbine was lacking in competition 

 with Frasera, in consequence of the great attraction of the latter for Apis 

 and Bombus. 



PENTSTEMON. 



Comparison. — Of the five species of Pentstemon employed, P. glaber, 

 glaucus, and gracilis grow native in the area, barbatus and unilateralis were 

 brought from the foothills, and halli from the alpine meadows. The 



