34 PROCEEDINGS OF THE ACADEMY OF [Feb., 



its existence. From this acorn grew the tree now on my grounds. 

 It is remarkably fertile, wholly destroying the " sterile " idea, even 

 though it were a hybrid, and with the leaves and skeleton characters 

 of Q. paluMris, as already noted. Seedlings from Delaware trees, 

 the acorns sent by Mr. Conmions, a well-known local botanist, all 

 retain the character of occasional entire leaves, but in other 

 respects coincide with Q. palustris. AVhile the absence of deep 

 lobing struck ]\Iichaux, it is remarkable that he did not note the 

 opposite in other cases. 



It is not unusual to note individual trees of Quercus palustris 

 with the leaves so deeply incised that there is left little of leaf- 

 blade but the strong veins and midribs. Indeed, this variation in 

 the lobing of leaves may be noted in all species of oak. There is 

 no need to call in hybridism to account for this varying condition. 

 We find in many plants a tendency to have lobed leaves in an early 

 stage and wholly entire at a later. The evergreen ivy, Hedera 

 Helix, is a familiar example. AVe now know that these changes 

 result from varying degrees of growth-energy, and not from any 

 external agency in which hybridism may be included. In the 

 light of modern knowledge, explanations of the past seem remark- 

 able. Referring to Quercus heterophylla Michaux says: " Ever}^ 

 botanist who has \"isited different regions of the earth must have 

 remarked certain species of vegetables which are so little multiplied 

 that they seem likely at no distant period to disappear from the 

 earth. To this class belongs the Bartram oak. ' ' "When we remem- 

 ber that this was said of a young tree, described as ' ' 30 feet high 

 and 8 inches in diameter," growing in the midst of numerous pin 

 oak trees of great age, that formed almost the chief oak character 

 of that region, and from which this young tree must have had its 

 origin, one can only surmise that for once INIichaux had lost his 

 usual high judicial ability. 



The main point of this note is to illustrate by the Bartram oak 

 the value, in settling important questions in long dispute, of the 

 discovery that old wood may change its direction so as to give a 

 specific chai'acter to the main branches or skeleton of the tree, and 

 incidentally to show that we gain a great point in biology when we 

 note how striking variations may occur by varying degi'ees of vital 

 energy, and without calliiig in tlie aid of survival, hybridism or of 

 any external agency. 



