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of the stem of a Bamboo is somewhat similar, but the vascular 

 bundles are not so conspicuous and the interior of the stem 

 is usually hollow, except at the joints. In the stem of a Tree 

 Fern also there is no distinct bark, and we find an exterior coat 

 consisting of the bases of fallen leaves and adventitious roots 

 and a central portion of soft tissue, which often disappears 

 and leaves a hollow in old stems, while between these lies 

 a ring of harder woody tissue which contains characteristic 

 vascular bundles, usually crescent-shaped and with a dark- 

 coloured border. 



