OF THE EASTERN UNITED STATES 357 



and monoclinic prisms of calcium oxalate, while a very few contain 

 gummy lignin. Sclerenchyme fibres are rare in this region. 



The phloem in relation to the cortex is comparatively broad. It 

 contains, besides soft bast, numerous islets of bast figures which 

 are accompanied by crystal fibres. The crystal fibres are com- 

 posed of rows of superimposed thin walled parenchyme cells, some of 

 which contain rosettes, others, monoclinic prisms of calcium oxalate. 

 The primary medullary-rays in this region are numerous and are 1-5 

 rows of cells wide. They broaden out toward the cortex in fan-shaped 

 fashion. 



The cambium zone is distinctly wavy in character. 



The xylem is traversed by numerous primary and secondary medullary 

 rays which are continuous with those of the phloem region. The cells 

 of these contain numerous starch grains and considerable tannin. The 

 tracheae are very numerous, occupying most of the wood area. Their 

 walls are pitted. No barred septa have been observed. The woody 

 fibres are generally quite narrow, taper-ended and extremely Hgnified. 



The secondary medullary-rays are from 1-2 to 1-3 cells wide, while 

 the primary rays vary from 1-4 to 1-5 cells in width. 



Tannin is present in cortex, phloem and medullary-rays. 



Comparative Morphology of Stems 



Gross Structure 

 Myrica cerifera, L. 

 A shrub or tree from 1 to 12 m. high, erect to ascending in habit and 

 having a tall crooked trunk 20 to 30 cm. in diameter, and upright or 

 spreading crooked branches which form a round-topped head. The 

 recent shoots are greenish to reddish brown, twigy-elongate at the ends 

 of branches or branchlets and bearing numerous leaf buds above and 

 flower buds below during the season The upper portions of these 

 shoots are densely covered with yellowish- and orange-red glands and a 

 sparse number of whitish non-glandular hairs. The lower portion has 

 fewer glands and hairs. Many reddish-white to white, raised, oval, 

 spotlike lenticels are scattered over the surface. These are slightly 

 elongated longitudinally and show a length of 5 mm. The branchlets 

 of second year's growth are reddish-brown and show a few glands but no 

 non-glandular hairs. The lenticels are larger, arranged longitudinally 

 and vary from .5 to 1.5 mm. in length. The branchlets in their lower 



