Oedeb 160.— FILICES. 

 s 



Order CLX. FILICES. Ferns. 



r Sjpm a perennial, creeping, horizontal 

 riiizome, or sometimea erect and arbores- 

 cent. Fronds (fruit-bearing leaves) va- 

 riously divided, rarely entire, with forked 

 veins, and mostly circinate vernation. 

 Frwdificaiion 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-colled, con- 

 taining numerous, minute spores. An- 

 Oieridia and pistiUidia formed after ger- 

 mination, on the young plant. (See figs^ 

 491—601.) 



Genera 200, speciea 2000.— A I.irge and in- 

 teresting order of flowerless plants, distin- 

 cnished for their elegant, plume-Hke foliage. 

 Thoy are usually a few Inches to a few feet 

 high, but some of tlie tropical species, as tho 

 Cyatheas of both Indies, are 15 — 25 feet high, 

 Vicing with the palms in eizo and beauty. 



Properties. — Generally mucilaginous and 

 mildly astringent, hence considered pectoral. 

 Aspidiuni and Ptcris are anthelmintic. Os- 

 muinda regalis has been successfully adminis- 

 tered for the rickets. 



Ohmr'oaUQti. — The fructification of the ferns, 

 with its various appendages, is too minute to 

 bo well observed by the naked eye ; but an 

 examination of it with the aid of a good lens 

 canuot fail to be interesting and satisfactory. 



739 Polypodium vulgare. T40 Frond. 741 

 Lobe of the frond enlarged, showing the Borl. 

 742 One of the sori enlarged, showing the spor- 

 angia. 748 One sporange further magnified, 

 bursting and discharging the spores. 744 Soruft 

 of Aspidium nnarginale coYered witll the indu- 

 sium, 745 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 revoluto fronds), (b) 



2 Sporangia on the back of tho fronds,— but involved in the revolute segm Noe. 8, Ifi 



— not involved ; segments flat, (c) 

 BcBOBDEit I. OPriIOGLOS3EJ3. (Sporangia naked, smooth, cartilaginous, 2- val ved ; no ring.) 



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



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



StrnoKDEn II. OSMUNDEjE. (Sporangia reticulate-roughened, papery, 2-valved, 



with no ring, spicato or paniculate.) — b Fronds palmate. Climbing Lyqodium. 3 



— ^b Fronds filiform. Erect Scnizji. 4 



— b Fronda 1— 2-pinnate Osmunpa. o 



Sheoeder III. POLYPODINE^. (Sporangia minute, on tho back of tho frond, 

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



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

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

 d Fruit-dots naked, having no indusium (special ^rvering). (e) 



e Fronds all alike, flat Fruit-dots orbicular Polypodium. 7 



Fronds sterile and fertile very different ; the fertile spike-like Stuuthioptbbib. 8 



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



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



h Indusium continuous all around the segment Ptkeib. 9 



h Indusium from tlie apex of the segm.— Mid vein central Cheil ANrnKs. 10 



— Midvein lateral or Adiawtttm. 11 



ll Indusium a reflected tooth at tho sinua between tho segments. . . .Dicesoma. 13 



