NATURAL SCIENCES OF PHILADELPHIA. 437 



November 2. 

 The President, Dr. Ruschenberger, in the chair. 







Twenty-eight members present. 



Natural Hybrids. Quercus heterophylla, Mx. Mr. Thomas 

 Meehan said, that in reference to the minutes of the last meeting 

 just read, he might offer a few additional remarks on Q. hetero- 

 phylla, and its connection with Q. Phellos. It was a subject 

 of much interest equally to the mere botanist, the student of the 

 origin of species, and to those who were investigating the fre- 

 quency or otherwise with which hybrids occurred in nature. 



He doubted, he said, whether hybrids often occurred naturally, 

 and yet with the supposed abhorrence of plants to use their own 

 pollen, and the consequent imitation which they extended to 

 foreign pollen to fertilize them, it would be remarkable if some 

 instances of hybridism did not occur, and perhaps remarkable 

 that it did not occur oftener than it was supposed to do. It was 

 such questions as these which gave the supposed hybrid origin of 

 this oak its chief interest. In this connection he referred to the 

 number of the Revue Scientifique then on the table, with an ab- 

 stract of some remarks of M. Ch. Naudin before the Academy of 

 Sciences of Paris, in which he says, that, of a large number of cases 

 of hybrids that he had experimented with, only two retained their 

 hybrid forms beyond two generations, and these two, grasses of 

 the genus JEgilops, lost their respective forms, and reverted to 

 that of the original female parent in four generations. 



Mr. Meehan said that the original tree described by Michaux 

 grew on the original Bartram estate. That tree had long since 

 been destined; but there were now large trees, both at Bartram's 

 and Marshall's, which were said by the late Col. Carr, who had 

 married Miss Bartram, and up to comparatively recent years 

 owned the garden, to be seedlings from that original tree. If this 

 were correct, it would sustain Naudin's views, as these trees were 

 so like the willow oak as to be scarcely distinguishable. They 

 only differ from the willow oak, in an occasional lobing of the 

 leaf, a matter of little consequence in determining a species in 

 this genus. It is more than likely, for reasons he would presently 

 state, that William Bartram found 3 7 oung plants witli lobed leaves 

 growing, and transplanted them to his garden, believing them to 

 have been seedlings of the Q. heterophylla, and not that they 

 were from seed actually gathered from the tree. 



In his description Michaux speaks of it as probably having Q. 

 imhricario, for one of its parents, but there is no proof nor pro- 

 bability that this species ever grew in these parts. It could not 



