THE CANE. 



Fin. 3. 



Structure of the Stalk. 



On cutting across a cane it will be seen 

 2 that it consists roughly of three parts, 

 a hard outer rind, and a mass of softer 

 tissue in the interior, interspersed with 

 fibres, the latter being more frequent 

 about the periphery of the stalk. The 

 rind is made up of a thick epidermis 

 with a strong outer cuticle, impervious 

 to water, and a layer of thick-walled 

 cells ; the function of the cuticle is to 

 prevent evaporation of water from the 

 stem of the cane, and to protect the 

 softer interior parts from mechanical 

 injuries ; the layer of thick-walled cells 

 gives rigidity and strength to the stem. 

 These thick-walled cells gradually pass 

 into the thin-walled cells of the ground 

 tissue, or parenchyma, which serve to 

 store up the sweet juice of the cane. 

 The fibres are known as the fibro- 

 vascular bundles ; they consist of the 

 wood vessels, sieve tubes and com- 

 panion cells, surrounded by thick- 

 walled fibres. 



A cross section of the cane, as 

 seen under the low power of a 

 microscope, is shown in Fig. 3. 



1. The epidermis, with thick 

 cuticularized walls. 



2. Thick- walled ground tissue of 

 the rind. 



3. A small vascular bundle ; these 

 are : found mainly in the outer portion of 

 the stem, and their function is chiefly 

 mechanical. 



4. An intermediate bundle with* 

 two vessels and a few thin-walled 1 , 

 phloem elements. 



5. Thick-walled fibres ; these are- 

 the mechanical elements of the bundles, 

 and are more numerous in the bundles, 

 towards the outside. 



