FILICES. (ferns.) 589 



parted ; the divisions lanceolate, acuminate, entire ; fruit-dots mostly in a double 

 series in each lobe of the frond, near the midrib. — South Florida. — Rootstock 

 large, creeping, copiously beset with lanceolate brown chaffy scales. Stipe 

 smooth, 8'- 10' long. Fronds 10' -15' long, two thirds as wide. 



3. VITTARIA, Smith. 



Sporangia on a continuous receptacle immersed in a furrow open outwardly 

 at or near the margin of the frond. Veins obscure, simple, connected at their 

 extremities by the receptacle. Fronds simple, linear, elongated. 



1. V. lineata, Swartz. Fronds nearly sessile, narrowly linear, elongated ; 

 midrib inconspicuous, lines of fructification near the margin. (V. angustifrons, 

 Michx. ) — On trees, South Florida. Fronds many from the short scaly root- 

 stock, l°-2° long. 



4. PTERIS, L. 



Sporangia borne on a transverse marginal receptacle connecting the ends of 

 the veins. Indusium continuous, formed of the membranaceous margin of the 

 frond, at first reflexed, at length pushed back and disclosing the ripened fructifi- 

 cation. Fronds 1 -3-pinnate or decompound. 



1. P. longifolia, L. Fronds lanceolate, pinnate; pinnee numerous, nar- 

 rowly linear, acuminate, obtuse at the base, the terminal one elongated, the 

 lower ones gradually smaller. — Key West. — Fronds l°-2° high, smooth. 

 Stipe more or less chaffy. 



2. P. Cretica, L. Fronds smooth, ovate, ternate or pinnate ; the lower 

 pinnae 2-3-parted, sessile, the upper ones decurrent ; sterile ones lanceolate, 

 or linear-lanceolate, finely serrate ; fertile ones narrower, entire, or spinulose- 

 serrate at the acuminate apex ; veins straight, simple or forked, close together, 

 almost at right angles to the midrib. — Shady woods, Middle and East Florida. 

 — Frond 6'- 10' long. Stipe smooth, very long and slender. 



3. P. aquilina, L. (Brake.) Fronds large, glabrous or somewhat hairy 

 beneath, broadly triangular, tripinnatc ; pinnules oblong or linear, entire or has- 

 tate or pinnately parted ; ultimate segments obtuse, oblong or linear, the termi- 

 nal ones often elongated, the margin reflexed or revolute ; veins simple or forked ; 

 indusium narrow, ciliated. — Common everywhere. — Stipe stout, 6' - 2° high. 

 Frond l°-2° long. 



Var. caudata (P. caudata, L.), with very narrow segments, the terminal 

 ones elongated, and both surfaces of the frond glabrous or even glaucous, occurs 

 in South Florida and along the Gulf coast. 



5. PELL^A, Link. 



Fruit-dots oblong or linear at the ends of the veins, confluent in a broad 

 marginal line of fructification. Indusium as in Pteris. Veins free, forked or 

 pinnate. Fronds mostly 1 -3-pinnate, smooth, mostly coriaceous. 



1- P. atropurpurea, Link. Fronds tufted, coriaceous, ovate-lanccolnte. 

 pinnate or below bipinnate ; pinnae opposite, rather distant, the lower ones 

 50 



