28 POLYPODIACEAE. 
12. PTERIS L. Sp. Pl 1073.5 °1753- 
Large, mostly coarse ferns, our species growing in sunny places, with variously divided 
or in some tropical species simple leaves, and marginal linear continuous sori which occupy 
a slender or filiform receptacle, connecting the tips of free veins. Indusium membranous, 
formed of the reflexed margin of the leaf. Sporanges pedicelled, provided with a vertical 
ring which bursts transversely. Stipes continuous with the rootstock. [Greek name for 
ferns, from the fancied resemblance of their leaves to the wings of birds. ] 
About too species of very wide geographic distribution, mostly of warm and tropical regions. 
Besides the following, three others occur in the southeastern United States. 
1. Pteris aquilina L. Brake. Bracken. 
(Fig. 61.) 
Pteris aquilina ¥,. Sp. Pl. 1075. 1753. 
Rootstock stout, woody, horizontal, subterranean. 
Stipes 1°-2° long, straw-colored or brownish ; 
leaves 2°-4° long, 1°-3° wide, usually glabrous, ter- 
nate, the three branches each 2-pinnate ; upper pin- 
nules undivided, the lower more or less pinnatifid. 
In dry or moist sunny places, distributed over nearly 
the whole of North America, except the extreme north, 
and over nearly the whole of the Old World. Ascends 
to 5000 ft. in North Carolina. Forms with pubescent 
lower leaf surfaces occur in southern New York and 
New Jersey. July—Sept. 
Pteris aquilina caudata (I,.) Hook. Sp. Fil. 2: 196. 1858. 
Pleris caudata ¥,. Sp. Pl. 1075. 1753- 
Pinnules sometimes linear and entire, or with the 
segments less crowded and the terminal lobe attenuate, 
narrow and entire. In sandy soil, New York to Florida 
and Texas, and in tropical America. 
135 CRYPTOGRAMMA R. Br. App. Franklin’s Journ. 767. 1823. 
Light green, alpine and arctic ferns with leaves of two kinds, the segments of the sterile 
much broader than those of the:fertile, the sporanges in oblong or roundish sori, which are 
at length confluent and cover the backs of the fertile pinnules. Indusium formed of the 
somewhat altered margin of the pinnule, at first reflexed to the midrib, so that the segments 
appear pod-like, at length opening out flat. Sporanges pedicelled, provided with a vertical 
ring which bursts transversely, borne at or near the ends of unconnected veins, copious, 
light brown. ([Greek, in allusion to the hidden sporanges. ] 
Two species, the following of northern North America, the other of boreal regions of Old World. 
1. Cryptogramma acrostichoides R. Br. American Rock-brake. (Fig. 62.) 
Cryptogramma acrostichoides R. Br. App. 
Franklin’s Journ. 767. 1823. 
aor acrostichoides Spreng. Syst. 4: 66. 
827. 
Rootstock rather stout, short, chaffy. 
Stipes densely tufted, straw-colored, 2/-6’ 
long, chaffy below, very slender; leaves 
ovate or oyate-lanceolate in outline, thin, 
glabrous, 2-3-pinnate, the sterile shorter 
than the fertile, their ultimate segments and 
pinnules crowded, ovate, oblong or obovate, 
obtuse; crenate or slightly incised; fertile 
leaves with linear or linear-oblong segments 
3/’-6’ long, 1’ or less wide, the margins 
involute to the midrib at first, at maturity 
expanded and exposing the light brown 
sporanges. 
Forming dense patches among rocks, Labra- 
dor and Hudson Bay to Alaska, south to Lakes 
Huron and Superior, in the Rocky Mountains to 
Colorado and to California. Summer. 
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