204 PROCEEDINGS OP THE AMERICAN ACADEMY 



EXPLANATION OF PLATES. 



Fig. 1. Young frond of Agamm Turneri about 3 cm. in lengtli. X f . 



Fig. 2. Tnmsverse section of stipe of a frond liiie Figure 1. cut. Cuticula. 

 0. c. Outer cortex, i.e. Inner cortex. X 175. 



Fig. 3. Transverse section of lamina of a similar frond, e. Epidermis, c. Cor- 

 tex. X 175. 



Fig. 4. Part of adult lamina, showing perforations in various stages. X h- 



Fig. 5. Section across basal part of lamina, showing various stages in forma- 

 tion of perforations, a, b, c, d. Successive stages. / Plane of 

 lamina. X 2. 



Fig. 6. Diagrammatic view of five successive stages, a, h, c, d, e, in tlie develop- 

 ment of a perforation, c'. Cortex, m. Medulla. 



Fig. 7. Detailed figure of an early stage (Fig. 6, o) of a perforation, e. Epider- 

 mis, c. Cortex. ??!. Medulla, x. Apex of depression. X 175. 



Fig. 8. Detailed figure of a later stage (Fig. 0, c). e, c, m, as in Figure 7. 

 X. Medullary tissue cut out by growth of epidermis, y. Fragment of 

 cortical tissue cut out. z. Cortex of upper surface beginning to 

 shrivel. X 175. 



Fig. 9. Detailed figure of section through a completed perforation (Fig. 6, e). 

 e, c, m, as in Figure 7, the right-hand portion being represented in 

 outline only. v. Kemnants of dead cortical cells. X 175. 



