NATURAL SCIENCES OF PHILADELrHIA . 215 



November H. 

 The President, Br. Ruschenberger, in the chair. 

 Twenty-three members present. 



Anthers of Ambrosia artemisixfolia. Mr. Meehan desired to 

 correct an error into which he had fallen, in some observations on 

 the Ambrosia artemisiasfolia, contributed to the Academ^y's Pro- 

 ceedings a few years ago. Among other things, he stated in tliat 

 paper that there were two classes of anthers in the flowers, one 

 barren, and surmounted b}^ a short horn, the other polleniferous, 

 and hornless. He had been led to re-examine the matter through 

 the kindness of Professor Asa Graj', who had written to liim, after 

 his remarks had been quoted in Hooker and Bentham's Genera 

 Plaufarum, expressing doubts as to the accuracy of the observ- 

 ation. He now found he was wrong. There is but one class of 

 stamens, and all have horns. He expressed regret for the error, 

 believing inaccurate observations the bane of science. He would 

 only say in extenuation that the error was one easily made. 

 The parts are exceedingl}^ small, requiring a strong glass to see 

 them. The small horn is bent down closely against the back of 

 the stamen, and does not become erect until the pollen has been 

 discharged. He thus had concluded it did not exist. Then the 

 pollen must be ejected in some way very rapidly' after the pollen 

 sacs have burst, and the dry membranous remains so freely mixed 

 with what appeared perfect anthers had misled him. The burst- 

 ing and emptying by the sacs of their pollen, and the erection of 

 the horn, he thought must take place suddenl}^ and early in the 

 morning, as he had found no change whatever in the various parts 

 of the inflorescence after 9 A. M. Pie had hoped to be able to 

 give the exaet time and manner of these actions, but the approach 

 of winter had destroyed the specimens, and he was unwilling to 

 let the season go over without correcting the error in the particu- 

 lars named. 



Dimorphism in Apples. Mr. Thomas Meehan said that of late 

 3"ears it had been an interesting question what influence was 

 exerted on the cliaracter of the fruit immediately by hyln'idiza- 

 tion. He had himself brought to the notice of the Academy, in- 

 stances which proved in some cases there was an immediate influ- 

 ence, as well as on the progeny of the fertilized fruit. But he 

 believed there was more claimed for this immediate influence than 

 the facts warranted. In the apple there had been many instances 

 in scientific journals of the highest charactei", in which it was 

 believed that two distinct fruits had combined in one apple b3' 



