1880.] NATURAL SCIENCES OF PHILADELPHIA. 353 



whether in past years they had borne burs in this manner or 

 not. 



It will be remembered that occasionally in a field of corn the 

 tassel, which is the staminate (innle) flower, has a number of 

 grains of corn intermixed. These grains come from pistillate 

 (female) flowers, occurring among the staminate ones; thus it 

 may be observed that our chestnut tree is not the only instance 

 of deviation from the regular laws of development. It has been 

 aroucd that a want of nutrition will aecoiuit for this and similar 

 instances, but the healthy appearance and vigorous growth of 

 the trees in question is not such that a lack of nutrition can well 

 apply. 



Mr. Thomas Meehan remarked that he believed instances of 

 the changes of flowers normally of one sex to the otlier, were oc- 

 casionally met with, though he could not refer to many without 

 further thought or investigation, but it occurred to him just then 

 that it Avas not unusual for some normally male spikes in Carex 

 to have female dowers among them. He had himself seen well 

 developed ovariums among the anients of Populus alba, and the 

 case of female flowers among the male catkins of willows, was 

 well known to teratologists. Reference had been made to his 

 papers on sex as influenced by nutrition. His view of sex, as 

 well known, was that in the earlier stages, between the cessation 

 of vegetative growth and reproductive growth, a vegetable cell 

 might be either male or female, and that the power of that cell to 

 assimilate nutrition, involved the question of sex. If a full sup- 

 ply was received, the female form resulted; if limited, the male 

 was produced. In most cases this assimilative power influenced 

 only the branches or cells in the immediate vicinity of the 

 flowers. There might be no difference in the cells of the whole 

 plant in a general way to avail themselves of a full supply of 

 nutrition. He did not know tiiat there was greater vegetative 

 strength in the plant of Maize, which bore some females among 

 the '' tassels '' or males, than there was in the normal plant. 

 There certainl}^ was no difl'erence in the vegetative strength 

 of plants of separate sexes in many classes of plants. But 

 there were instances which proved that the whole individual 

 plant was influenced by laws of nu.rition when the question 

 of sex was involved. The female Hemp, the female Spinage, 

 the female Croton, when the plants were wholly bi-sexual, were 

 cases he could readily call to mind where vegetative vigor favored 

 the whole plant. 



The common Ambrosia artemisisefolia, which often grows so 

 thickly over cultivated fields as to a;)pear as a regular farm 

 crop, each plant fighting for nutrition with its neighbor, pro- 

 duces almost wholh' male blossoms ; the few females are found 

 at the base of the male spikes. But when we go to the maize or 

 the potato fields, where the plants are few and well fed, we may any 

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