36 Bulletin ^Yisconsi)l Natural History Society. [Vol. 7, Nos. 1-2. 



In this instance it is in the purple flower that we find a higher 

 percentage of long-tongued visitors. In the observations on Lia- 

 tris spicata, made in Racine Co., they cover 2 days only, and for 

 this reason the list, consisting of 23 visitors, can hardly be con- 

 sidered complete enough to be of much value for comparison. 



INTRODUCED SPECIES. 



Among the species dealt with in this study, there are 7 which 

 have found their way into our flora from Europe, all of which have 

 succeeded in gaining a strong, and permanent foothold. Accord- 

 ing to the length of their tubal florets they may be arranged in the 

 following order : 



Species. 

 Achillea millefolium, (white). 

 Anthemis Cotula (white rays, and yellow disk). 

 Chrysanthemum leucanthemum (white rays, and yellow 



disk). 

 Tanacetum vulgare (yellow). 

 Cirsium arvense (purple). 

 Arctium Lappa (purple). 

 Cirsium lanceolatum (purple). 



Tube length 1 mm. 



We have already considered the average percentages for the 

 3 native white-flowered species having a tube 1 mm. in length. A 

 comparison of these with the averages for the corresponding in- 

 troduced species (the first 3 named above) shows how remarkably 

 close the two sets of species agree with each other. 



Allotr. Hemitr. Eutr. 



Native 52.9 41.7 5.4 



Introduced 53.8 42.7 3.5 



The same may be said of the yellow Tanacetum vulgare when 

 compared with the yellow goldenrods Solidago canadensis and 

 S. juncea. Here are the figures : 



Allotr. Hemitr. Eutr. 



Native 56.9 36.1 7.0 



Introduced 53.0 38.2 8.8 



Tube length iy 2 mm. 



There are 3 native species belonging to this group, and Cirsium 

 arvense is the only introduced species with the same tube leigth. 

 The average percentages are as follows : 



Allotr. Hemitr. Eutr. 



Native 32.6 52.7 14.7 



Introduced 37.2 51.3 11.5 



