The Gleicheniacecc and Lindsayc<z. 
141 
Hymenophyllaceae, which we have seen some reason to suppose 
may he regarded as showing comparatively primitive types of 
Filicinean vascular structure. The isolated or almost isolated 
Fig. 39. Glcichcnia linearis ( dichotonia), Series of transverse sections 
through stele of node. sc. p., sclercnchymatous pocket; i. ph., internal 
phloem, confined to adaxial side of pocket; a. b. i. ph., acroscopic branch of 
internal phloem ; par., parenchyma, forming lower end of pocket ; st. r., stele 
of root arising from base of leaf-trace. From Boodle. 
internal endodermis of forms like G. circinata, G. dicarpa and G. 
linearis is difficult to regard as anything but a structure reduced, 
