OBSERVATIONS UPON THE PHENOMENA OF PLANT-LIFE. 335 



Here, then, was a composite tree, consisting, tirst, of a root of quince, then a 

 pear tree, upon this an inverted pear tree which had branches consisting of 

 inverted quince roots, and these were surmounted by pear shoots of two unlike 

 kinds. Upon such a specimen it would be very difhcult to comprehend the 

 working of the imaginary syphons of Dr. Pettigrew, already described. 



In order to illustrate the fact that the return of the elaborated sap was not 

 the result of the force of gravity, a pendant branch of weeping willow was 

 girdled last June. The enlargement was on the lower side of the girdled place, 

 showing that the flow of the material formed in the leaves was constantly 

 towards the roots. 



To learn whether sap would flow from the bark on the upper side of a gir- 

 dled place, a stem of white willow, an inch in diameter and ten feet high, 

 was selected, and a ring of bark one inch long removed. The girdled place 

 Avas then wrapped in oiled paper, so as effectually to exclude the air and the 

 light. On the fifteenth of October, one month after girdling, the paper was 

 taken olf, and the specimen examined. The wood appeared dead and brown, 

 and was covered with a mucilaginous fluid Avhich appeared to have come from 

 above. There was no sign of growth below the girdle, but above it the stem 

 was decidedly enlarged, and a callus had descended a quarter of an inch and 

 developed upon itself a bud, as if about to strike out for air and light. No 

 bleeding from the bark was observed in any case worthy of mention, the near- 

 est approach to it being in the flow of turpentine from the bark and sap-wood 

 of the Avhite pine. 



Among the specimens of natural grafting obtained during the past year, 

 perhaps the most remarkable was a fine bunch of mistletoe growing as a para- 

 site upon a branch of oak. This was kindly procured for the College museum 

 by Prof. J. W. Mallet, LL. D., of the University of Virginia. The shrub is an 

 evergreen, and its roots penetrate the bark and sap-wood of the tree on which 

 If feeds, appropriating the crude sap and forming a wood of a totally different 

 sort from that of its support, and having an ash peculiar to itself. In fact, 

 the several species on which it is produced seem to serve merely as so many 

 diflPerent soils on which it can thrive. As the oak branch was dead beyond 

 the mistletoe, it would seem to have been injured by the abstraction of its sap 

 and its exhalation from the foliage of the parasite. 



A specimen of red maple was brought to the College by Mr. Austin East- 

 man, of Amherst, which exhibited a single trunk with one heart, formed by 

 the natural union of two shoots, which were nearly three feet apart, and were 

 nnited about six feet from the ground. The main trunk was eight inches in 

 diameter. 



Another specimen, found in Pelham, shows two white pine trunks, joined 

 like the Siamese twins, at about four feet from the ground. This, when sawed 

 open vertically, showed how the union had been effected. A branch of one 

 had lodged in the angle made by a branch of the other with its parent trunk. 

 As the tree grew, they were fastened together, and, under the pressure thus 

 caused, the bark was flattened until it almost disappeared, and soon the new 

 wood formed over the scar and made the grafting complete. 



BUT THE GEAFTING OF ROOTS 



is still more common and curious. They seem to cohere without the least 

 difficulty, especially those of the white pine, which is doubtless owing to the 

 softness of the bark and young wood, and the fact that they grow so nearly 

 at the same level in the earth. 



