PRACTICAL WOKK. NO. V. 209 



c. vascular bundles forming an irregular ring ; 



d. pith ; 



e. medullary rays. 



Sketch a single bundle, shewing its xylem, phloem 

 and cambium, and compare your sketch with that of a 

 bundle in the Sunflower, noting that in the Oak there is 

 a large amount of thick-walled wood fibre. 



ii. Examine a transverse section of the stem of an 

 Oak seedling, and shew on your sketch that the bundles 

 do not yet form a ring, but are isolated somewhat as in 

 Sunflower. 



iii. Examine an older stem with a simple lens. Cut 

 the surface clean with the razor reserved for rough work. 

 Make a sketch of the surface as seen with the simple lens, 

 shewing the annual rings of wood and the medullary rays. 

 The larger vessels in the spring wood are easily made out. 



Peel the stem and from a piece of the peeled wood 

 cut transverse sections which must be mounted in dilute 

 glycerine. Shew on your sketch the annual rings due to 

 the approximation of the denser autumn wood with the 

 succeeding spring wood. 



iv. Cut tangential longitudinal sections of a small 

 piece of the same stem, and mount in dilute glycerine. 

 Make a sketch of your section, shewing the medullary rays 

 as lenticular groups of cells, well seen in the harder parts 

 (fibres) of the wood between those lighter tracts which 

 are the large dotted vessels. 



v. With a knife split the remnant of your stem 

 longitudinally into quarters. Then cut radial longitudinal 

 D. E. B. 14s 



