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THE BOTANICAL MAGAZINE. 



[Vol. XXII. No. 2.iS. 



equall, being less than the probable error. As to the mode, 

 the former shows a strong mode on 13-14< and a lesser mode 

 on 16, while in the latter, two distinct modes were seen on 

 13 and 16. 



Second collection. Sept. 11. 



Both the mean and modes were alike in these two lots, but 

 the C were tolerably greater in the former, as in the first 

 collection. Thus these two places affected, on the whole, nearly 

 equally the variation of rays of this Aster, but the thickness of 

 vegetation in the railway-embankment caused more disturbance 

 on them, positively and negatively. 



In comparing the means with those of the former collection, 

 in the railway it increased 0.170 rays and in the bank it decreased 

 only 0.003 rays, and thus no seasonal fall of rays could be seen, 

 though 27 days had elapsed. 



As I had no opportunity for further visit, it was not deter- 

 mined what change would occur in the later part of the season, 

 but in a plant with such a small number of rays as this Aster,^^ 

 a rapid fall seems to be not probable, and here, at least during 

 the first one month, no indication of decrease could be seen, 

 except perhaps with a slight indication of increase. 



As to the mode, that on 13 to 14- and on 16 was equally 

 probable as the sinus on 15, and no other feature was seen in 

 this early season. 



1) In Aster prenanthoides it decreased during 11 days (Sept. 27— Oct. 8) from 

 30.769 to 20.335 (Shull, 1. c. p. 145), and in Chrys'jnlhcmum Uucanihcmum during 25 

 days (July 5-30) from 27.87 to 21.36 (Towek, 1. c. p. 315). Also compare the follow- 

 ing species. 



