TISSUE SYSTEMS 



349 



Concentric Bundles. — Of this form we have again two varie- 

 ties. In most the wood is central, and is surrounded by a layer 



FiGf. 734. 



i''i(/. 734. Stele of stem of Feru, composed of three fused oonceutric bundles. 

 en. Endodermis. pe. Pericyole. ph. Phloem, px. Groups of protoxylem. 



'...-jO« 



Fig. 735. 



-./ X. 



Fig. 735. Ooaoentrio bundle of Draccena. x. Xylem. ph. Phloem. 



