160 



XI. THE DICOTYLEDONOUS STEM WOODY TYPE. 



tearing up the macerated sections longitudinally with needles- 

 under the low power of the microscope. The prepar- 

 ation will then show the especial preponderance of the 

 wood-fibres (Fig. 63, A, B). The swelling of the walls 

 causes the pits to appear still more minute ; they show 

 as oblique clefts. The short parenchymatous cells, re- 



\j 



Q J) E * 



FIG. 63. Tilia parvifolict. Elements of the secondary wood and bast, 

 isolated by maceration. A and B, wood-fibres (libriform) ; (7, wood- 

 parenchyma ; D and E, trachei'des ; F, segment of a duct : G, bast-fibre 

 (x!80). 



cognisable by their contents, lie scattered between the 

 wood-fibres, and are either separated, or, corresponding 

 with their origin from cambial cells, still joined into 

 short threads (c), which resemble in outline the wood- 

 fibres, and lie scattered between them. We find, further, 

 but in smaller number, the spirally-thickened trachei'des, 

 in outer contour either more resembling the wood-fibres (J5J), or 



