8 POLYPODIACEAE 
7. CHEILOGRÁMMA Blume. 
Epiphytes, relatively small, with simple leaf-blades. Sori linear, but the lines some- 
times interrupted, nearly marginal. Veins reticulated. 
1. Cheilogramma lanceolàtum (L.) Blume. Rootstocks creeping. Leaves numer- 
ous; petioles 2.5-5 cm. long ; blades simple, 15-32 cm. long, 1 2-16 mm. wide, entire, often 
somewhat crisped, tapering both ways, with prominent midrib and obscure immersed 
veins ; veins anastomosing, the outer ones free and enlarged at their apices: sori antemar- 
ginal in a mostly continuous line near the apex.  [ Tuenitis lanceolata ( L.) R. Br. ] 
On trees, Old Rhodes Key, Florida. Also in tropical America. 
8. PTERIS L. 
Relatively large plants, with petioles continuous with the rootstock and variously di- 
vided leaf-blades. Sori marginal, linear, continuous, occupying a slender or filiform re- 
ceptacle, connecting the tips of thefree veins. Indusium membranous, single, formed from 
the reflexed margin of the leaf-blade. Veins free. 
Lower divisions of the leaf-blades undivided. 1. P. longifolia. 
Lower divisions of the leaf-blades forked or pinnate. 
Leaflets 7-10 mm. wide, the upper scarcely decurrent. 2. P. Cretica. 
Leaflets 5 mm. wide or less, the upper strongly decurrent. 9. P. serrulata. 
1. Pteris longifólia L. Leaves somewhat spreading ; petioles 15-30 cm. long, clothed 
below with pale brown scales; blades oblong-lanceolate, 3-6 dm. long ; leaflets linear, 4-10 
mm. wide, entire, sessile: veins close, usually once branched : indusium yellowish brown. 
Peninsular Florida and the Keys, and Louisiana. Also widely distributed in the tropics. 
2. Pteris Crética L. Leaves several; petioles 15-30 cm. tall, straw-colored or pale 
brown ; blades 15-30 cm. long; leaflets usually 2-6 opposite pairs, sessile, the sterile con- 
siderably broader and spinulose-serrulate, the lower pairs often parted nearly to the base 
into 2 or 3 linear segments : indusium pale: veins free, parallel, simple or once forked. 
Peninsular Florida and the Keys. Also in tropical regions generally. 
3. Pteris serrulàta L. f. Leaves several; petioles 15-22 cm. long, naked, pale or 
brownish ; blades ovate, 20—45 cm. long, 2-pinnatifid, the rachis with a wing 2-4 mm. wide 
at the top, thence narrowed downward ; leaflets in 6 or more distinct opposite pairs, the 
upper simple, the lower with several elongated linear segments on each side; the sterile 
portions spinulose-serrate. 
On old walls, South Carolina to Louisiana, doubtless escaped from cultivation. A nativeof China. 
9. PTERÍDIUM Scop. 
Coarse plants growing in open sunny places, with ternately compound leaf-blades. Sori 
marginal, linear, continuous, rising from a vein-like receptacle connecting the ends of free 
veins. Indusium double, an outer formed by the reflexed margin of the leaf-blade and a 
second, more delicate with the vein-like receptacle. 
Ultimate segments of the leaf-blades approximate at the base. ode ili . 
Ultimate segments of the leaf-blades, L5 mm. apart at the base. 6 pe ceni 
1. Pteridium aquilinum (L.) Kuhn. Rootstock stout, woody, horizontal. Leaves 
erect, sometimes 2 m, tall; petioles straw-colored or brownish, 3-6 dm. long ; blades 6-12 
dm. long, usually glabrous, ternate, the three divisions each 2-pinnate, the lower leaflets 
more or less pinnatifid. [Pteris aquilina L.] 
In sunny places, throughout North America, Europe and Asia. Variable. BRACKEN. BRAKE. 
2. Pteridium caudatum (L.) Maxon. Leaves erect, 1-4 m. tall, or sometimes taller ; 
blades 3-4-pinnate ; divisions pinnatifid, the ultimate segments narrow, with recurved mar- 
gins, remote from one another, scarcely decurrent on the rachis except near the apex, the 
larger with 1-12 similar but shorter segments. [Pteris aquilina var. caudata (L.) Hook. ] 
In sandy soil, Florida and Texas. Also in the West Indies. 
10. ADIANTUM L. 
Graceful plants of rocky hillsides, woods and ravines, with much divided leaf-blades. 
Petioles and their divisions slender or filiform, polished and shining. Sori short, margi- 
nal, borne on the under side of the reflexed and altered portion of the leaflets, which serves 
as an indusium. MAIDENHAIR FERN. 
