OEDBB 160. FILICES. 



ORDER CLX. FILICES. FERNS. 



Stem a perennial, creeping, horizontal 

 rhizome, or sometimes erect and arbores- 

 cent. Fronds (fruit-bearing leaves) va- 

 riously divided, rarely entire, with forked 

 veins, and mostly circinate vernation. 

 1'buctificatton occupying the back or mar- 

 gin of the fronds, arising from the veins. 

 Sporangia (spore-cases) of one kind, scat- 

 tered or clustered in sori, 1-celled, con- 

 taining numerous, minute spores. An- 

 th&ridia and pistillidia formed after ger- 

 mination, on tho young plant (See figs. 

 491501.) 



Genera 200, specie* 2000. A large and in- 

 teresting order of flowerless plants, distin- 

 guished for their elegant, plume-like foliage. 

 They are usually a few inches to a fev,' feet 

 high, but some of the tropical species, as the 

 Oyathea? of both Indies, are 15 25 feet high, 

 vicing with the palms in size and beauty. 



Properties. Generally mucilaginous and 

 mildly astringent, hence considered pectoral. 

 Aspidium and Pteris are anthelmintic. Os- 

 tnunda regalis has been successfully adminis- 

 tered for the rickets. 



Observation. The fructification of the ferns, 

 with its various appendages, is too minute to 

 be well observed by the naked eye ; but an 

 examination of it with the aid of a good lens 

 cannot fail to be interesting and satisfactory. 



879 



741 



Polypodium vnlgare. 740 Frond. 

 Lobe of the frond enlarged, showing the sori. 

 742 One of the sori enlarged, showing the spor- 

 angia. 743 One sporange further magnified, 

 bursting and discharging the spores. 744 Sorus 

 of Aspidium marginale covered with the indu- 

 sium. 746 Same, side view. 



SUBORDERS AND GENERA. 



Frond cauline, solitary, straight in vernation. Stem erect, (a) 



Fronds cauline, several, palmate (or radical and filiform), (b) 



Fronds all radical, clustered (never filiform), circinate in vernation. (2) 



2 Sporangia spiked or panicled, naked (not involved in revolute fronds), (b) 



2 Sporangia on the back of the fronds, but involved in the revolute segm Nos. 8, 20 



not involved ; segments flat (e) 

 SUBOKDKP. I. OPHIOGLOSSE^E. (Sporangia naked, smooth, cartilaginous, 2-valved ; no ring.) 



a Fructification spicate. Frond entire, reticulate- veined OPIIIOGLOSSITM. 1 



a Fructification paniculate. Frond divided, fork-veined BOTIIYCHIUM. 2 



SUBORDER II. OSMUNDEJE. (Sporangia reticulate-roughened, papery, 2-valved, 



witli no ring, spicate or paniculate.) b Fronds palmate. Climbing. LYGODIUM. 3 



b Fronds filiform. Erect SCHIZ^E. 4 



b Fronds 1 2-pinnate OSMUNI>A. 5 



SUBORDER III. POLYPODINE./E. (Sporangia minute, on the back of tho frond, 

 valvelcss, torn open by the elastic ring which encircles it vertically.) 



C Sporangia scattered singly all over the surface (not in sori), naked ACEOSTICUM. 6 



c Sporangia collected in dots (sori) springing from the veins, (d) 

 d Fruit-dots naked, having no indusium (special covering), (e) 



e Fronds all alike, fiat. Fruit-dots orbicular POLYPODICM. 1 



e Fronds sterile and fertile very different ; the fertile spike-like STEUTUIOPTERIS. S 



d Fruit-dots invested with special coverings (indusia). (g) 



g Fruit-dots marginal ; indusium a narrow, reflected edge of frond, (h) 



b. Indusium continuous all around the segment PTEP.IB. 9 



b. Induvum from the apes of tho segm. Midvein central CHEII.ANTHES. 10 



Midvein lateral or AIHANTUM. 11 



b. Indusitmi a reflected tooth at the sinus between tho segments DICKSONIA. 13 



