' 88 THE AMERICAN NATURALIST. | (Vor. XXXIX. 
son of Lucas' Lot 1 with Lots 2 and 3 or 4 that this procedure 
tends to give a decidedly lower mean than is obtained from a 
random sampling of heads directly collected in the field. 
A slight typographical error in the paper of Lucas to which 







































Frequency 




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aS 





ee | | 
TUE 
| 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 


























smi P E 
Fic. r.— Frequency polygon. Ray flowers of Rudbeckia. 
reference has been made, was noted. In the legend to Fig. 2 
the number of heads in the combined Lots 2 and 3 is given 
as 468, while in the text Lot 2 is stated to have included 225 
heads, and Lot 3, 240 heads. 

