470 EXPLANATION OF THE FIGURES. 



FIG. 



16. Transverse section of the place of attachment of a more developed frond. 

 The circle in the middle shows the place of insertion of the cylindrical 

 stipes (within it are the vascular bundles) ; the rest of the tissue be- 

 longs to the stipule. 



17, 18. Transverse sections through the stipule and stipes of the same frond, 

 one and two lines higher up. 



19. Longitudinal section of a similarly developed frond. Twice the natural 



size. 



19 5 . Lateral half of the stipule of the latter frond, after the removal of the 

 leafy portion. 



20. Apical region of a half-developed frond, seen from above, x 100. 



PLATE XXXIV. 



1. Swollen end of a runner of Nephrolepis midulata, in longitudinal section, 



X 20. 



2. Perfect and growing tuber of the same plant. Natural size. 



3. Shoot of a similar tuber, detached from the latter. It has already pro- 



duced two runners. 



4. Longitudinal section of the terminal bud of Poly podium vtdgare, x 250. 



5. 6. Apical aspect of the tips of the stem of the same fern, x 250. 



7. Apical view of the tip of the stem of Polypodium dryopteris. 



Pigs. 8 12. Platy cerium ctlcicorne. 



8. Transverse section of the perfect stem. Natural size. 



9. Transverse section of the stem close under the growing terminal bud. 



Natural size. 



10. Net of vascular bundles of the stem seen from above. Natural size. 



11. The same seen from below. 



12. Longitudinal section of the bark of a root, x 100. 

 12*. Some cells of the latter, x 450. 



PLATE XXXV. 



1. Terminal bud of a very vigorous autumn shoot of Equisetum limosum, x 400. 



2. Longitudinal section of the end of the bud of a lateral shoot of Equisetum 



arcense, at the beginning of May, X 200. 



3. Equisetum limosum. Apical view of an end of a stem divided by a transverse 



section, underneath the third cell from the apex. The edges of contact 

 of the cells within the stem, underneath the cell of the first degree, are 

 shown by dotted lines, x 500. 



4. Similar terminal bud; the section has passed somewhat lower down; x 



200. 



5. Transverse section of the stem of Equisetum limosum close under the apex, 



X 300. 



