120 PKOCEEDINGS OF THE ACADEMY OF [1887. 



tion was in the period of life when they assumed activity. In the 

 Chestnut ( Castanea) it Avas nearly 25 years before they grew into 

 destructive agencies, and hence there was smooth bark to the Chest- 

 nut for nearly a quarter of a century. In the oak rough bark from 

 the development of the cork cells, began at about ten years, in the 

 Sassafras at live years, in some they started at one and occasionally 

 the same season. In the Beech they grew the first season, and 

 only worked under the outer cuticle, which they threw off as fine 

 film annually. Handling a branch of Beech at some seasons, a 

 filmy deposit would be left in the hands, which was the fine silky 

 bark of the Beech. Hence the Beech had never rough bark. 

 This fact should show mechanical action had no part in rifting the 

 bark. Mechanical action should split a Beech as well as any other 

 tree. 



Returning to the Plum, he remarked that the development of 

 the cork cells were in many respects the same as in the Beech. 

 They started on their destructive errand before the annual groAvth 

 was fairly over, destroying the thin outer cuticle as it progressed. 

 It was this that gave the silvery tint to Plum wood with which all 

 must be familiar. This was never seen on Peach Avood. This 

 character was exhibited in all the samples of supposed hybrids sent. 

 There was nothing whatever to distinguish them from pure Plums 

 so far as this character was concerned. 



As for the flowers, the plants were sterile because of peculiar 

 abortion in the reproductive organs. The carpels instead of being 

 consolidated, ending in a single style as in the ordinary Plum, had 

 become distinct, and they were ten processes difficult to say whether 

 they resembled stamens or pistils most. There were no attempts to 

 form perfect stamens or petals, but the bud scales had a faint rosy 

 margin as if there existed a slight dis]30sition to make petals out 

 of them. They Avere remarkable examples of monstrosity in Plum 

 flowers, but nothing to indicate any action of the Peach therein. 

 They were evidently sterile because they were monstrous, and not 

 that they Avere hybrids. The foliage had a more peachy look than 

 customary Avith Plums, so far as mere outline Avas concerned, but 

 it is well knoAvn that Avhen there Avas a disturbance of sexual 

 characters, the whole system of groAvth Avas apt to be disturbed. 

 It Avas possible the Plum and the Peach Avould hybridize. It would 

 be of much interest to science could the possibility be proA^ed a 

 fact. It Avas due to science to say these specimens did not prove it. 

 The chief interest in the specimens, he thought, dwelt in the fact 

 that amidst all the changes in characters brought about by some 

 abnormal agency, the cortical peculiarities as influenced by the 

 cork cells remained the same. 



April 19. 



The President, Dr. Leidy, in the chair. 



Fifteen persons present. 



