SECT. II. THE STEM. 275 



ditches, and are produced, no doubt, by the agency 

 of the same cause that gives a similar figure to the 

 root. 



Sometimes it happens that a stem instead of as- The flat- 

 suming the cylindrical form common to the species, stem. 

 assumes a compressed and flattened form similar 

 to the herbage of the Cactus. Of this anomaly 

 I have occasionally observed a specimen in the 

 stem of the Tamus communis, which from a cy- 

 linder of about a quarter of an inch in diameter, 

 its natural size and shape, was converted into a 

 flattened and oblong production of about an inch 

 in breadth. But the best specimen of the anomaly 

 I have ever met with, was in the case of the stem 

 of an Ash -tree (PI. IX. Fig. 6). The tree stood 

 in a hedge row in the parish of Stow Upland, 

 Suffolk, and in the autumn of ) 80Q, seemed to be 

 about twelve or fifteen years of age, or at any rate 

 to be about twelve or fifteen feet in height. Of this 

 tree the top and perpendicular shoot which had in 

 the preceding summer extended to the length of 

 twenty inches, was compressed into a flattened and 

 oblong production, fluted on both sides as well as 

 furnished with some buds, and of about an inch in 

 breadth, but expanding at the summit to the 

 breadth of nearly two inches, and surmounted with 

 a row of buds of between twenty and thirty in 

 number ; the shoot of the preceding year having 

 been cylindrical and now measuring about half an 

 inch in diameter. 



