EXPLANATION OF THE PLATES. 



DlCKSONlA, SITOLOBIUM. Pinna of D. pnnctilobula, Hook. (I)', portion of a pinna lo 

 (2), enlarged ; and a fruit-dot in its cup-shaped indasiam (8). 



TAB. XII. 



CY8TOPTERI9. Piece of the frond of 0. bulbifera, Bernh. (1); a lobe In fruit (?\ 

 enlarged; and a small portion more magnified (8), bearing a fruit-dot with Its in<!u- 

 sinm thrown back. 



WOODSIA. Small frond of W. glabella, R. Sr. (1) ; a part of a fruiting pinna of thesume 

 (2), magnified; and a separate indusium (8), more magnified; a piece of a fruitful 

 pinnule of W. obtusa, Torr. (4), enlarged; and a fruit with the opened Indus! r. in 

 beneath (5), more magnified. 



A8PIDIUM. Pinna of A. (Dryopteris) marginale, Swarta (1); and a magnified fruiting 

 portion (2) ; piece of A. (Polystichum) acrostichoides (3) ; and a small fruiting por- 

 tion (4), magnified. 



ONOCLE A. Sterile and fertile frond of O. sensibilis, L.; front view of a fruiting contracted 

 pinnule, enlarged (1) ; and the same laid open and viewed from the other side (2) : 

 on one lobe the sporangia are removed from the veins. 



TAB. XTLI. 



SCHIZ^EA. Plant of 8. pusilla, Pwrsh; a fertile pinna with eleven sporangia (1), mag- 

 nified; and a separate sporangium (2), more magnified. 



LYGODIUM. Summit of frond of L. palrnatum, Swarte(l), with fertile and sterile divi- 

 sions ; a fruiting lobe enlarged (2), with two of the lower scales, or indusia, removed, 

 displaying a sporangium under each ; and a sporangium more magnified (8). 



OSMUND A. Small piece of the frond of O. Claytoniana, L. (1), with a fertile and a 

 sterile pinna; a portion of the fruit magnified (2) ; and one sporangium more mag- 

 nified (8). 



BOTRYCH1UM. Plant of B. lunarioldes, Swarta ; and a portion of the fruit (1), with six 

 sporangia, magnified. 



OPHIOQLOSSUM. Frond of 0. vnlgatum, L.; and a portion of the fruiting spike en- 

 larged (1). 



Genera of Eqnisetaceae, Lycopodiacese, and 

 IIydroptcridc. 



TAB. XIY. 



EQUISETUM. Upper part of fertile plant of E. limosum, L. (1) ; one of the shield- 

 shaped scales or receptacles of the spike, with the six sporangia underneath (2), 

 enlarged; same seen from below, discharging the spores (8); a magnified spore 

 with the club-shaped filaments spreading (4) ; and (5) the same with the filament a 

 coiled up. 



LTCOPODIUM. Plant of L. Carolinianum, L.; and (1) a magnified scale of the spike 

 removed, with the sporangium in its axil, discharging powdery spores. 



8ELAG INELL A. Plant of 8. rupestrla, Spring ; part of a fertile spike, enlarged (1) ; fcale 

 from the upper part of it (2), with its sporangium, containing innumerable powdery 

 spores; scale from the base (8), with its sporangium containing few largo spores; 

 and (4) three large spores. 



