120 VIII. THE MONOCOTYLEDONOUS STEM. 



origin the wood consists only of trachei'des with bordered pits, 

 surrounding a very reduced bast ; the radially-arranged ground- 

 tissue cells between the bundles may be considered as medullary 

 rays, strictly comparable with those of Dicotyledons and Gymno- 

 sperais. The whole of the secondary ground-tissue is stained 

 brown. The bundles often anastomose tangentially. The cells of 

 the cambium-ring are swollen by the reagent and stained violet. 

 Clearer spots on the ring indicate more swollen but less stained 

 rudiments of the vascular bundles. The rounded cells of the 

 cortex are violet, the cork-cells yellow-brown, but the innermost 

 layer, the cork-cambium, is also violet. 



