290 PROCEEDINGS OF THE ACADEMY OP 



In the specimens to whicli I refer, I counted from seven to ten 

 bractlets. This numerical variation I am confident results from 

 the splitting, so to speak, of some or all of the primary bractlets, 

 as specimens were observed wliich exliibited all the transitional 

 forms, from a slight indentation at the apex to partial and comi)lete 

 division. 



June 17. 

 The President, Dr. Ruschenberger, in the chair. 

 Twenty-three members present. 



Laws of Sex in Juglans nigra. Mr. Thomas Meehan said he 

 had at various times during the past few years called the attention 

 of the Academy to specimens of numerous plants which illustrated 

 the principle that sex in plants was the result of grades of vitality; 

 or, as it had been suggested, viabilit}' ; and that this power of life 

 was a mere matter of nutrition; the highest grades of vitality 

 only producing the female sex. Almost any monoecious plants 

 furnished the necessary evidence of the truth of this position, 

 and wliat he had said or written on the subject had always been 

 done more to direct attention, and to lead others to examine plants 

 themselves, than that the facts were exhausted. He believed that 

 in the main the principle had been so generally accepted by natu- 

 ralists, that it seemed unnecessar}' for him to say any more on the 

 subject, but let it now work its own way. At the meeting of the 

 American Association, at Dubuque, last 3'ear, which he had not 

 the pleasure of attending, the subject was introduced; and though, 

 as he gathered from the public papers, the principle was to a cer- 

 tain extent admitted, objection was made that possiblj^ tlie weak- 

 ened shoot or axis bearing male flowers was a result of the pro- 

 duction, and if so it would sliow rather a great expenditure of 

 vital force in their formation, than afford a pi'oof of the principle 

 under discussion. He was astonished at the sugojestion at the 

 time, exhibiting as it did, he thought, a careless reading of his 

 papers; as he had stated, and exhibited the facts supporting the 

 statement to the Academy, that, especially in coniferte, the weak- 

 ening process had been going on for several seasons prior to the 

 production of male flowers. In the pine and spruce, for instance, 

 he had distinctly stated, that only tliose branches the most favorably 

 situated to derive the greatest benefit from nutritive forces bore 

 female flowers. These branches in time naturally became shaded 

 by succeeding growths. The partial shade was injurious to per- 

 fect nutrition. A few years of these circumstances weakened the 

 branch, and after being thus weakened, the male catkins appeared. 

 There were of course otlier agencies at work besides siiade ; what- 

 ever they were, the result in sex was the same. He did not think 



