ORDER 159. FILICES. 417 



A large and interesting Order, distinguished for their elegant, plume- 

 like foliage. They are usually a few inches to a few feet high, but some 

 Df the Tropical species, as the Cyatheae, are 15 to 25 feet, vieing with the 

 Palms in size and beauty. 



gW The stipe is the stalk of the frond, and the rachis its continuation through it. The 

 oinnae (orpn.) are the first divisions of a divided frond (often called leaflets). Pinnulcc 

 (or pnl.) are the first divisions of the pinnae when further divided. Segments (seg.) are 

 \hejlnal divisions, and the partial divisions of the segments are lobes, &c. The sori (fruit- 

 dote) are either naked, or covered with an indusium (see cut). 

 POLYPODIACE^E. THE TRUE FERNS, with fronds mostly radical, circinate in bud. Fporangia i 



sori, pedicellate, with a vertical, elastic ring, opening transversely... (/) 



CYATHEACE^E. THE TREK FERNS, with fronds on an erect trunk. Sporangia as in l...(e) 

 HYMENOPIIYLLACE^E. PELLUCID FKRNS ; sporangia in a cup and on a thread... (d) 

 SCIIIZjECE^E. Very slender vines or fronds. Sporangia with a ring-crown at apex. ..(c) 

 I OSMUNDI ACE^E. Fronds stout, radical. Sporangia with no ring, 2-valved. . .(&) 

 f OPHIOGLOSSACE^E. Frond single (in our species), on an erect stem. Sporangia with no ring. . .() 



a Fruit in a spike. Frond entire, reticulate-veined OPHIOGLOSSUM. 1 



o Fruit in a panicle. Frond divided, fork -veined BOTKYCH JUM. 2 



ft Fronds pinnate or bipinnate, with straight, forked veins OSMUNDA. 3 



e Fronds palmately lobed. Stems climbing, 3 4f LYGODIUM. 4 



c Fronds linear-filiform, undivided, a few inches high SCHIZ^EA. 5 



< Fronds 3-parted, middle division sterile, the lateral paniculate ANEIMIA. 6 



d Fronds pellucid or opaque. Sporangia with a transverse ring TRICHOMANKS. 7 



Fruit-dots in little round cups. Trunk and leaves smooth CYATHEA. 8 



Fruit-dots becoming entirely naked. Fronds prickly or hairy ALSOPHILA, 



Fruit-dots enclosed in the reflexed tip of the lobe, with two valves B ALANTIU M. 22 



/ Sporangia scattered singly all over the surface (not in sori), naked. ..(g) 

 f Sporangia collected in dots (sori) growing from the veins... (A) 



g Fronds simple or pinnate. Pinnae on short petiolules ACR'OSTICHCM. 10 



g Fronds forked at the summit, entire below, the sterile different PLATYCERIUM. J I 



h Sori (fruit-dots) naked, having no covering of any kind... (A;) 



h Sori involved (at first) in the rolled segments of the panicled fertile frond. . .(m) 



h Sori not involved, but invested with special coverings (called indusia). ..(n) 



% Fronds smooth or scaly, never powdery. Sori distinct, roundish POLYFODIUM. 12 



k Fronds covered with powder on the back. Sori in many dorsal lines GYMNOGRAMMA. 13 



k Fronds powdery or scaly on the back (bipinnate). Sori in a marginal line NOTHOL.SNA. 14 



It Fronds linear, simple. Sori in a continuous line on the split margin. Fla VITTARIA lineata. 



m Fertile frond bipinnate, segments berry-like. Veins reticulated ONOCLKA. 15 



m Fertile frond pinnate, pinnae moniliform. Veins forking STRUTHIOPTERIS. 16 



m Fertile fronds bipinnate, segments oblong, soon opening ALLOSORUS. 17 



n Sori marginal, indusia only the reflexed altered margin of the frond. ..(o) 

 n Sori marginal, indusium double a scale combined with the margin. ..(p) 

 n Sori dorsal, oblong or linear, indusium attached to the side of a vein...(</) 

 n Sori dorsal, round or roundish, indusiura on the back or the tip of a vein. . .(x) 



o Fronds of 2 kinds, the fertile contracted. Sori continuous to apex LOMARIA. 18 



o Fronds all similar, smooth. Indusia continuous all around. Stipe green or brown.. PTERIS. 19 

 o Fronds woolly, Ac. Sori separate or continuous. Stipe brown, hairy CHEILANTHES. 20 



Fronds smooth. Sori separate. Stipe black and polished ADIANTUM. 21 



p Indusium a 2-lipped cup at the edge of the segments DICKSONIA. 22 



f Indiwium an entire cup or goblet at the edge of the segments DATALLIA. 23 



q Sori parallel to the mid-vein, the indusia, opening toward it...(r) 



q Sori oblique to the mid-vein, borne laterally on the veinlets. . .(s) 



r Sori linear, nearly continuous, in 2 rows, sunk in the frond WOODWARDIA. 24 



r Sori oblong, remote, in two rows and superficial. Stipes black DOODIA. 25 



r Sori linear, in 1 double row, the whole length of the segment BLECHNUM. 26 



r Sori oblong, in 1 short double central row. Frond finely cleit ONYCHIUM. 27 



a Indusia single, regularly arranged, in 2 rows ASPLENIOM. 28 



1 Indusia single, scattered irregularly. Frond simple or lobed CAMPTOSORUS. 29 



ludusia double, regularly arranged. Frond simple SCOLOPENDRIUM. 30 



