20 



THE MICROSCOPE. 



Feb. 



wood, the one nearest the wood being the last formed. 

 It also contains woody fibre and lactiferous vessels. 



In the beech, where the bark is smooth, the growth 

 takes j)lace in the liber layers chiefly, the cellular envel- 

 ope and cork merely expands to make room for the en- 

 largement of the stem. The cork is composed of flat tab- 

 ular cells, not of coarse cork tissue. 



XI. — SECTION OF STEM OF SYCAMORE. 



Here again can be seen the six parts of a stem as 



pointed out above but with wuiaiiuns peculiar to this 

 tree. The four rings of w^oody fibre are now very prom- 

 inent, and the medullary rays to the number of over 

 50 stand out with great jjrominence. 



The woody structuie of plants is composed of woody 

 fibres and ducts except in the Coniferse where the latter 

 are wanting. The woody structure of a stem of more 

 than a year's growth has the appearance of being divided 

 into concentric rings and each of these rings is supjjosed 



