_ 99 _ PINUS. 



58. Histology of Stem. Draw a transverse section of an older stem under the low 

 power to show the annual rings : and under the high power to show spring and autumn 

 tracheides and cork. 



59. Histology of Stem. Draw a longitudinal section of the stem under the high 

 power to show : epidermis ; cork ; cortex ; resin-canals ; sieve-tubes ; phloem paren- 

 chyma -, cambium ; tracheids with bordered pits ; medullary rays in both cross and 

 longitudinal sections; pith. 



