FILICES. (FERNS.) 



celled, borne on the under side of the fronds or along their margins, often 

 covered by a membrane of various shape (indusium or involucre), contain- 

 ing numerous exceedingly minute spores. 



Synopsis. 



Suborder I. POLYPODIXEiE. Sporangia collected in dots, lines, 

 or variously shaped clusters (sort or fruit-dots), or in indefinite masses, 

 cellular-reticulated, mostly pedicelled ; the stalk running into a vertical 

 incomplete elastic ring, the straightening of which ruptures the ripe 

 sporangium on the inner side, discharging the spores. — Fronds simple 

 or variously divided. 



Tribe I. ACROSTICHEjE. — Sporangia collected in large or indefinite masses on the 

 back of the frond : indusium none. 



1. ACROSTICIIUM. Sporangia covering the lower surface of the upper pinnae. Veins retic- 



ulated. 



Tribe II. POLYPODIES. — Fruit-dots roundish, distinct, destitute of indusium, 

 borne on the back of the frond. 



2. POLYPODIUM. Fruit-dots scattered variously on the back of the frond, borne at or near 



the ends of the veins. 



Tribe III. — "VITTARIEjE. — Sporangia borne in a continuous elongated marginal or 

 sub-marginal furrow. 



3. V1TTARIA. Fronds simple, narrowly linear. 



Tribe IV. PTERIDE^E. — Fruit-dots marginal, separate or continuous. Indusium 



formed by the refiexed margin of the frond or its lobes, opening toward the midrib. 

 » Indusium thin and membranaceous, continuous around the margin of the fertile pinnae. 



4. PTERIS. Sporangia borne on a transverse intramarginal veinlet. 



5. PELLiEA. Sporangia borne on the ends of the veins, at length confluent. 



* * Indusium rarely continuous, mostly formed of the refiexed ends of the lobes or divisions 

 of the pinna? or pinnules. 



6. CIIEILANTIIES. Sporangia borne on the veins beneath the refiexed margin of the 



frond. Pinnules with a midrib. 



7. ADIANTUM. Sporangia borne on the under side of the indusium. Midrib none or 



eccentric. 



Tribe V. BLECHNEX. — Fruit-dots dorsal, linear or oblong, borne on transverse 

 veins parallel to the midrib. Indusium fixed by its outer margin, and opening at the 

 inner one. 



8. BLBCHNUM. Fruit-dots linear, elongated, covered by a continuous indusium. 



9. rVOODWARDIA Fruit-dots linear-oblong, in a series near the midrib, covered bj sep- 



arate indusia. 



Tribe VI. A SPr.ENIE.7E. — Fruit dots dorsal, linear or oblong, oblique or at right 

 angles to the midrib. Indusium fixed by one margin to the veinlet, opening at the 

 other. 



10. 0AMPTO8ORU8. Fruit-dot* straight or onrred, Mattered Irregularly on the more or leu 



reticulated veins, or being each oilier in pairs. Frond simple. 



11. 8.8PLENU If, Fruit-dots oblique, on the upper aide oi the veins, rarely on both sides of 



them. \ eins free. 



