CELLULAR TISSUES. 



335 



lated ducts seen in fig. 178. In a section from tho 

 India-rubber-tree, fig. 177, No. 2, a network of these lac- 

 tiferous tubes will be found filled with a brownish or 



Fig. 179. 



!, A portion of the leaf of Sphagnum, showing ducts, vascular tissue, and spiral 

 fibre in the interior of its cells. 2, Porous cells, from the testa of Gourd- 

 seed, communicating -with each other, and resembling ducts. 



granular matter ; that in fig. 178 is an enlarged view of 

 this tissue from the wood of an exogen, taken near the 

 root. 



I, Reticulated ducts. 



Fig. 180. 

 2, A vertical section of Fern-root. 



In many plants external to the cuticle, there exists a 

 very delicate transparent pellicle, without any decided 

 traces of organisation, though occasionally somewhat gra- 

 nular in appearance, and marked by lines that seem to 

 be impressions of the junction of the cells in contact with 

 each other. In nearly all plants, the* cuticle is perforat 



