28 



POLYPODIACEAE. 



12. PTERIS L. Sp. PI. 1073. 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 son 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 100 species of very wide geographic distribution, mostly of warm and tropical regions. 

 ]U -i.k-s the following, three "others occur in the southeastern United States. 



i. Pteris aquilina L,. Brake. Bracken. 

 (Fig. 61.) 



Pteris aquilina L. Sp. PI. 1075. 1753. 



Rootstock stout, woody, horizontal, subterranean. 

 Stipes i-2 long, straw colored or brownish ; 

 leaves 2-4 long, i-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 (L,. ) Hook. Sp. Fil. 2: 196. 1858. 



Pteris caudata L. Sp. PI. 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. 



i 



13. 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. 



i. Cryptogramma acrostichoides R. Br. American Rock-brake. (Fig. 62.) 



!,>Kramma acrosliclmides R. Br. App. 

 .klin's Journ. 767. 1823. 



Allosnrits acnxitichmdes Spreng. Syst. 4 : 66. 

 1827. 



Rootstock rather stout, short, chaffy. 

 Stipes densely tufted, straw-colored, 2 / -6 / 

 long, chaffy below, very slender ; leaves 

 ovate or ovate-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 

 $"-6" long, i" or less wide, the margins 

 involute to the midrib at first, at maturity 

 expanded and exposing the light brown 

 poranges. 



patches among rocks, Labra- 

 dor an. 1 HwUon Hay to Alaska, south to Lakes 

 i<>r. in the Kooky Mountains to 

 lo and to California. Summer. 



