342 THE WOODY STEM 



together with its lightness, makes it useful to man for 

 a great variety of purposes. 



PRACTICAL WORK. 



(1) Make a sketch of a winter branch of horse-chestnut (or 

 beech) showing several years' growth. Mark terminal buds, 

 lateral buds (distinguishing dormant buds) covered with winter bud 

 scales, leaf scars, bud-scale scars, lenticels ; also (in horse-chestnut), 

 if present, the scar of a fallen inflorescence. Mark also the 

 parts of the branch originally formed in each year, beginning with 

 last season and working backwards. Dissect a large terminal 

 bud. 



(2) Make a diagrammatic sketch showing the structure of any 

 sprouting bud (sycamore is very suitable, but almost anything 

 will do) after the first foliage leaves are clear of the bud scales, 

 marking winter bud scales, foliage leaves, elongating internodes 

 and terminal bud. [Opening buds preserved in spirit should be 

 provided if fresh material is unavailable owing to the season.] 



(3) Examine the transverse section of a woody twig about 

 three years old, first with a hand lens, then with the low power 

 of the microscope. [Sycamore is again suitable, but elm or 

 lime will do equally well.] Draw a diagram under the low power, 

 showing (a) the cork ; (b) the outer cortex ; (c) the inner cortex ; 

 (d) the pericycle ; (e) the secondary phloem ; (/) the cambium ; 

 (g) the secondary xylem with the annual rings, and in each the 

 spring and autumn wood ; (h) the principal secondary rays ; (i) the 

 primary xylems ; (_;') the pith. 



(4) Examine the branch of Portugal Laurel that has been 

 kept with its end dipping into red ink, or a watery solution of 

 eosin. Split it longitudinally and note that the red solution 

 has eosin in the wood only. 



(5) Make diagrammatic sketches of the three faces (transverse, 

 radial and tangential) of the segment of oak trunk provided, 

 showing 



On the transverse section the annual rings, the large spring 

 vessels which appear as small holes in the wood, the masses of 

 fibres making up the great bulk of the wood, the broad secondary 

 rays crossing the cambium and extending through the functional 

 living phloem of the inner bark (yellow brown) into the dead 

 phloem (red brown) cut off between the dark layers of cork of 

 the outer bark. 



On the radial face the spring vessels appear as grooves in the 



