THE LIFE-HISTORY OF A FERN 



[CH. 



All these parts of the Fern-Plant consist of tracts of tissue differentiated 

 to subserve distinct functions. The most notable is the Vascular Skeleton, 

 which appears in the Male Shield Fern as a cylindrical network of strands 

 within the massive axis (Fig.i,E, F). It throws off branches on the one hand 



Fig. I. Dryopteris {Nephrodiuin) Filix-nias, Rich. A = stock in 

 longitudinal section: z/ = apex : j/ = stem: (5 = leaf-stalks : // = one 

 of the still foldedleaves : ^= vascular strands. ^ = leaf-stalk bearing 

 at /' a bud with root (w), and several leaves. C= a similar leaf-stalk 

 cut longitudinally, bearing bud (/i), with root {w). /? = stock from 

 which the leaves have been cut away to their bases, leaving only 

 those of the terminal bud. The spaces between the leaves are filled 

 with numerous roots, w, 7v'. j5' = stock from which the rind has 

 been removed to show the vascular network (,(,'•). F=a. single mesh 

 of the network (foliar gap) enlarged, showing the insertion of the 

 leaf-trace strands. (After Sachs.) 



into the leaves, where they ramify and extend upwards to the extreme tips 

 and margins. On the other hand strands of vascular tissue, springing from 

 the leaf-bases, extend towards the tips of the roots, and laterally into their 

 branchlets. The Vascular System is thus a connected conducting system 

 throughout the plant. It is embedded in soft parenchymatous tissues, 



