2l8 



Keegan: The Wild Cherry. 



sometimes in worm-shaped rows and formed of rather broad, 

 round, and moderately thick-walled cells ; scleroblasts also 

 occur here in a distribution very irregular ; in short, the entire 

 bast-layer possesses a very singular and almost unique radiated- 

 lamellar structure, as it has been described, forming- generally 

 a series of parallel zigzag lines deviating alternately to and 

 from the side of the strongly curved bast-medullary rays. 

 The periderm is sub-epidermic and composed of uniform flat- 

 celled integuments of cork which are extremely tough, and 

 resist for a long time the action of the weather ; hence when, 

 through the pressure of the expanding wood elongating their 

 walls, they finally burst, they adhere to the surface as tough 

 membranous flaps and scrolls ; this structure remains thin and 

 living during a long time, and it is only at an advanced age, 

 and then only at the base of the trunk, that a liberian lignification 

 ensues of sufficient strength to produce a darkish rhytidome 

 longitudinally chinked and furrowed. The chemical constituents 

 of the bark and wood are well marked and of considerable 

 interest. The starch, which from the beginning of March has 

 remained in copious quantity in the reserve tissues of the stem 

 and branches, begins to dissolve from the bark about one 

 month after the autumn fall of the leaf, i.e., about the end of 

 November, while at the same time in the wood it is only 

 slightly diminished. During the winter also the protoplasm of 

 the rind-medullary rays is specially rich in fat, and a considerable 

 quantity of glucose is also present along with tannin-vesicles 

 at the same time. At all times a white wax, an ill-defined bitter 

 principle (probably an impure or decomposed alcoholic sugar), 

 a large quantity of oxalate of calcium, free phloroglucin 

 (especially in the bast-fibres and medullary rays), and phloba- 

 phene which penetrates the periderm turning it red-brown, may 

 also be found in the tissues of the bark, which in addition 

 contain about 10 per cent, mineral -matters (ash), consisting of 

 about 45 per cent, lime, 15 soda, 5^ magnesia, 21 silica, etc. 

 Large gum-druses appear sometimes in the living parts of the 

 bast as well as in the dead outer portion of the primary cortex, 

 or even enclosed in the periderm. The wood is capable of 

 enclosing a considerable quantity of starch ; the vessels and 

 fibres are very rich in glucose in summer, but not in winter ; 

 tannin occurs in the medullary rays, in the parenchyma, and the 

 pith ; free phloroglucin is found in the parenchyma, and in most 

 of the cells of the pith ; the wood has only about 0*28 per cent, 

 ash. The rooting of the tree is powerful, it being composed of 



Naturalist, 



