312 



Sandwich Islands, under the name of Nehai. Diplazium esculenturn, Cyathea 

 medullaris, Pteiis escalenta, and Gleichenia dichotoma, are also occasionally 

 employed for food in different countries. Pteris aquilina and Aspidiam Filix 

 Mas have even been used in the manufacture of beer, and Aspidiurn fragrans 

 as a substitute for tea. Agdh. [Inf. seeds Botrych.] 



Examples. Ferns have been divided into several sections, of which the 

 following are the most generally adopted : 



I. PoLYPODIACEjE. 



Gyratae, Swartz Syiiopsis Filicum, (1806). — Filices vers, Willd. Sp. Pi 5. 99. 

 (1810).— Polypodiaceae, R Brown Prodr. 145. (1810); Agardh Aph. 

 116. (1822) ; Kaulfuss Enumeration 55. (1824) ; Bory in Diet. Class. 6. 

 586. (1824.) 



Thecal furnished with a vertical, usually incomplete, annulus ; bursting irre- 

 gularly and transversely. (Polypodium, Pteris, Adiantum.) 



II. GLEICHENEjE. 



Schismatopterides, Willd. I. e. 69. (1810).— Gleichenea?, JR. Br. I. c. 160. 

 (1810) ; Kaulfuss I. c. 36. (1824) ; Boryl. c. (1824.) 



Thecal furnished with a transverse, occasionally oblique, annulus, nearly 

 sessile, and bursting lengthwise internally. (Platyzoma, Gleichenia, Merten- 

 sia.) 



III. OsMUNDACEiE. 



Osmundaceae, R. Br. I. c. 161. (1810) ; Agardh I, c. 115. (1822); Kaulfuss 

 I.e. 42. (1824); Bonjl. c. (1824.) 



Thecae without any annulus, reticulated, striated with rays at the apex, 

 bursting lengthwise, and usually externally. (Osmunda, Schizaea, Lygo- 

 dium.) 



IV. Dan.eace.9e. 

 Agyratae, Swartz Synops. (1806).— Poropterides, Willd. I. c. 66. (1810).— 

 Danaeacese, Agardh I. c. 117. (1822).— Marattiaceee, Kaulf. I. c. 31. 

 (1824); Boryl. c. (1824.) 



Thecae sessile, without any ring, concrete into multilocular sub-immersed 

 masses, opening at the apex. (Marattia, Damea.) 



V. Ophioglosse^e. 



Ophioglosseae, R. Br. I. c. 163. (1810) ; Agardh Aph. 113. (1822) ; Kaulfuss 



I. c. 24. (1824) ; Bory I. c. (1824.) 



Thecae single, roundish coriaceous, opaque, without ring or cellular reticula- 

 tion, half 2-valved. Vernation straight. (Ophioglossum, Botrychium.) 

 To which Dr. Hooker adds : 



Parkeriace,e. 



Parkeriaceae, Hookey Exot. Fl. t. 147. (1825) ; t. 231. (1827); Hooker ei 



Greville Icones Filicum, t. 97. (1828.) 



Thecae scattered, sessile, marked with a broad, almost obsolete, very short 

 annulus, which is sometimes distinct and nearly complete. Sporules large, 

 3-cornered, striated. (Parkeria, Ceratopteris.) 



