XHE FERN FAMILY. 473 



Section 1. 

 Sori upon the underside of the frond, in the form of spangles, bars, or a con- 

 tinuous mai'ginal braid. Thecse girt by an elastic ring. Fronds circinate 

 while young. 



* 

 Trond quite simple, varying from three inches long and 

 an inch broad to two feet long by two to three 

 inches broad, heart-shaped at the base, pointed, 

 smooth, and bright grass-green. Sori in deep 

 brown bars,,sloping from the midrib to the margin. 14. Habt's Tongue. 



Frond more or less divided, pinnatifid, or branched ; the divisions termed 



" pinnules." 



A. 

 Lower pinnules the longest, or nearly so, usually giving the leafy part of the frond 

 a broad base, or even rendering it triangular. The leafy part, at all events, 

 not tapering down into a point ; and confined, or nearly so, to the upper 

 part of the rachis. 



Frond simply pinnatifid. Sori without indusia. 



Pinnules slightly serrate, one or two inches long. Sori 



large, circular, and yellow. Frond oblong .... 1. Common Polypody. 

 Pinnules deeply cleft, the lowest pair projecting for- 

 wards. Sori small, numerous, dark -brown. 



Frond triangular, finely hairy 2. Beech-feen. 



Frond repeatedly subdivided. 



Sori forming a continuous marginal braid. Pinnules 

 and their divisions veiy numerous. 

 Fronds six to nine inches high, densely tufted, fine 



and delicate pea-green, resembling parsley . . 16. Paeslet-feen. 

 Fronds two to six feet high, and two to three feet 

 broad, solitary, tough, and robust ; brown in 



old age 18. Beake-fern. 



Sori scattered over the under surface of the pinnules. 

 Pinnules five to ten. Sori linear. Fronds dark 

 blueish-green, two to three inches high, 



densely tufted 13. Wall-eue Feen. 



Pinnules and their divisions very numerous. Sori 



circular. Frond more or less triangular. 



Frond with three distinct branches, deflexed where 



they spring from the rachis; six to fifteen 



inches high, and very brittle. Sori without 



indusia 3. Oak-feen. 



Frond with many pairs of branches, all in one ) 7. Beoad-leaved Syl- 

 plane. One to three feet high. (Fig. B.)..) van Shield-febn, 



