* 
80 
Fig. 6. 
Old root of Christmas Tree. 
a, position of primary xylem (see Fig. 5) ; b, protoxylem; c, second- 
ary wood added to primary xylems by a certain amount of division of 
the cambium; c', secondary xylem formed from cambium formed from 
inner cortex; d, phloem; e, sclerenchymatous strand external to primary 
phloems; f, f', inner cortex; g, outer cortex; li, medullary ray; i, muci- 
lage canal; k, cork; 1, bundles formed by the second cambiums formed 
in the outer cortex. 
