1909] Gracnicltcr, Wisconsin Floivers and Their Pollination. 53 



and i mm. wide. The lobes of the corolla spread out nearly hori- 

 zontally. Gradually the stylar branches reach a length of 5 mm. 

 and become widely divergent, thereby favoring geitonogamy. 



Repeated observations during 3 seasons have furnished the 

 following list of 58 visitors : 



EUTROPOUS. 



Bees : 1, worker, s. and c. p. ; 4, male, female and worker, s. and 

 e. p.; 13, worker, s. ; 17. male, s. ; 34, female, s. ; 35, female, s. and c. p.; 

 36, female, s. and c. p. 



HEMITROPOUS. 



Bees : 99, male, s. ; 105, female, s. and c. p. ; 107, male, s. ; 114, 

 male and female, s. and c. p.; 118, female, s. and c. p.; 121, female, s. 

 and c. p. ; 132, female, s. 



Wasps: 149; 202 — both s. 



Flies: 270; 283; 288; 298; 304; 307; 313; 315; 316; 319; 322; 

 330 ; 332 ; 333 ; 334 — all s. or f . p. 



Butterflies and moths: 455; 460; 467; 475; 493; 501— all s. 



ALLOTROPUS. 



Wasp: 218, s. 



Flies : 254 ; 360 ; 369 ; 372 ; 377 : 378 : 379 ; 3S4 ; 385 ; 398 ; 400 ; 401 ; 

 413 ; 443 ; 444 — all s. or f. p. 



Beetles : 528 ; 530 ; 538— all s. 



Bug's : 554 ; 559 — both s. 



Eutrop 7 s= 12.1% 



Hemitrop 30 = 51.7% 



Allotrop 21 = 36.2% 



12. Eupatorium purpureum L. Joe-Pye Weed. 



The blooming period, lasting from about July 20 to Septem- 

 ber 16 covers rather completely that of E. perfoliatum. A head is 

 composed of 15 to 18 florets and measures only 3 to 4 mm. across. 

 The decidedlv sweet-scented flowers are light purple, and the 

 whole inflorescence (florets, bracts and pedicels) has a purple ap- 

 pearance. The floret is represented by a narrow tube 4 mm. in 

 length and only about Y mm. wide at the mouth of the floret, with 

 the corollar lobes erect, or barely spreading. In this species there 

 is ample opportunity for geitonogamy to take place between florets 

 of the same head, as also of neighboring heads, since the stylar 

 branches become profusely interwoven. Change of color to a 

 darker hue of purple appears in the advanced stages of the flowers. 

 Altogether the heads are much more loosely grouped than in our 

 white-flowered species of Etipatorium and the inflorescence does 



