NATURAL SCIENCES OF PHILADELPHIA. 101 



April 4, 1871. 

 The President, Dr. Ruschenberger, in the chair. 

 Thirtj'-two members present. 



Mr. Thomas Meehan, referring to the two-leaved division of 

 Pinus of Graj^'s Manual^ said that Pinus mifis was especially 

 named as having sometimes three leaves in a fascicle ; but in two 

 others of that section, P. inops and P. jmngens, he found the so- 

 called leaves in threes almost as abundantly as in the former one. 

 But the chief interest was that in all three species the three-leaved 

 bundles became more numerous as the growth of the season ap- 

 proached its end. In many instances the fascicles just beneath 

 the terminal buds were mostly in threes, and iu those cases, where 

 a second wave of growth had occurred, the terminal fascicles were 

 almost wholly in .threes. He thought that these indications of 

 order in their production might eveutualh' lead to the discovery 

 of the plan on which the fascicles were produced. It would, at 

 least, appear that in all two-leaved fascicles the germs of three 

 were present, and that it depended on some varying phase of 

 growth whether they were all developed or not. 



Mr. M. also said, in regard to the Acei-' rubrum, that he had 

 examined a large number of trees this season in order to test defi- 

 nitely whether there was any difference between the brown-flowered 

 form and the darker one, that had hitherto escaped the attention 

 of botanists. He found that there was no difference, but that as 

 a general rule the brown ones were male ; and it was the brown 

 filaments which gave them this color. There were, however, oc- 

 casional trees of both sexes which favored either color. But he 

 found that there were no trul}' hermaphrodite flowers amongst 

 them, and therefore the description of the books, " polj-gamo- 

 dioecious," was not strictly correct. In manj' female trees there 

 were apparent stamens, but the filaments were almost Avanting, 

 and he had been unable to find any of the anthers which they 

 bore, polleniferous. These abortive stamens hardl}' extended at 

 any time beyond the minute petals ; while the true stamens in the 

 male flowers had filaments extending a half inch or more bej'ond 

 the petals. He suggested that the fact of the apparently herma- 

 phrodite flowers in Ace?^ ruhrum being really pistillate was per- 

 haps a small matter in itself; but it would have much interest to 

 those who were observing how numerous were the species which 

 fell in with Darwin's discovery, that many plants took especial 

 pains to avoid self-fertilization. 



1871.] 



