EXPLANATION OF THE PLATES. 634 



DICKSOlfIA, gSITOLOBroM.— Pinna of D.pnnctilobnla, Bboh.O-); portion of a pinnule 

 (2), enlarged; and a fruit-dot in its onp-sbaped luduaium (8). 



Tab. XII. 



CTBTOPTERIS.— Piece of the frond of 0. bulbifera, £em7b. (1); a lobe in frnit (2), 

 enlarged; and a small portion more magnified (8), bearing a frnit-dot with its indu- 

 sinm thrown back. 



WOODSIA.— Small frond of W. glabella, E, Sr. (1) ; a part of a fruiting pinna of the same 

 (3), magnified ; and a separate indnsium (8), more magnified ; a piece of a fruitful 

 pinnule of W. obtusa, Torr. (4), enlarged ; and a fruit with the opened indusium 

 beneath (5), more magnified- 



A8PIDIUM. — Pinna of A. (Diyopterie) marginale, Siomie (1); and a magnified fruiting 

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

 tion (4), magnified. 



ONOCLEA.— Sterile and fertile frond of O. sensibilis, X./ front view of afruiting contracted 

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

 on one lobe the sporangia are removed ftom the veins. 



Tab. XIII. 



SOHIZ-^A.— Plant of S. pnsilla, Purah; a fertllo pinna with eleven sporangia (1), mag- 

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



LTGODIUM. — Summit of frond of L. palmatum, Swartu (1), with fertile and sterile divi- 

 Bions ; a fruiting lobe enlarged (3), with two of the lower scales, or indusin, removed, 

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



OSMUNDA.— Small piece of the frond of 0. Claytoniana, L. (1), with a fertile and a 

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

 nified (8). 



BOTETOHIUM.— Plant of B. Innarioides, Swarb; and a portion of the fruit (1), with six 

 sporangia, magnified. 



OPHIOGLOSSTJM.— Frond of O. vulgatum, L.; and a portion of the fruiting spike en- 

 larged (1). 



Genera of Eiinisetaceae, Liycopodiaceae, and 

 Hydropterides. 



Tab. XIV. 



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 undernoatli (3), 

 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 filaments 

 coiled up. 



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

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



SEL AG-IKELL A. — Plant of S. rupestris, BprVng ; part of a fertile spike, enlarged (1) ; scale 

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

 spores; scale from the base (3), with its sporangium containing few large spores; 

 and (4) three large spores. 



