PTERIDOPHYTA— LYCOPODINiE 



157 



primary bundles. In their downward course tlie fused masses of 

 wood are found to separate again and rejoin in other ways, the 

 anastomoses causing the transverse section of the stem to pre- 

 sent different patterns at different levels. The endodermis is 

 usually thick-walled, and surrounds a layer which occupies the 

 place of a perioj'cle, but which is really cortical and not stelar 

 in its origin. This layer gives rise to the adventitious roots. 

 The root is similar in structure to the stem, but it contains 



Fig. 915. Section of stem of Lycopodium. ep. Epidermis, ev. Endodermis. 

 pe. Pseudo-pericycle. p.r. Grroups of protoxylem. ph. Phloem. After Sachs. 



fewer bundles of wood and bast. Its apical meristem is com- 

 posed of small cells. 



The stem or tuber of Phylloglossum cont.ains little vascular 

 tissue. Bundles from the leaves and roots anastomose where 

 they enter it, and from the network a single strand passes 

 up to the peduncle of the cone. 



Both Psilotum and Tmesipteris agree with Lycopodium in 

 being monostelic, with bmidles arranged radially. The coi-tex of 



