462 



APPENDIX. 



leaflet is again divided, also arranged in two opposite rows. 

 We shall return later to the mature leaf. 



Note that the young leaves are curiously coiled, each being 

 rolled up on itself like a watch-spring, from tip to base ; the 

 expansion, or unrolling, of the leaf should be watched in 

 early summer. Not only is the main leaf -stalk rolled up in 

 this way, but the leaflets are also rolled up on themselves. 

 On picking off the scales which cover the growing tip of 

 the stem, the youngest leaves can be seen ; in their first 

 year the developing leaves consist chiefly of the stalk, the 



FOLIAR GAP 



Pig. 2. Part of the Vascular 

 System of Male Fern dis- 

 sected out. 



^-INDUSIUM 



.. SPORANGIA 

 -- PLACENTA 



Fig. 3. Pinnule of Male Fern bearing Sori. 

 The indusium has been removed from one 



sorus, the indusium and sporangia 



from another. 



rest of the leaf being very little developed. At the very tip, or 

 growing-point, itself still younger leaves can be seen, as minute 

 projections from the soft and delicate tissue of the stem apex. 



On cutting across the stem, we find that a large part of its 

 thickness is made up by the old leaf-bases. The whitish 

 ground tissue contains starch and gum, and in this tissue are 

 embedded numerous brownish strands the vascular bundles. 

 The central ring of thicker bundles belongs to the stem 

 itself, while the thinner bundles towards the outside belong 

 to the leaves (Fig. IB). At the outside of the stem there is 



