POLYPODIACEAE. 



VOL. I. 



6. Woodsia obtusa (Spreng.) Torr. Blunt- 

 lobed Woodsia. Fig. 28. 



Polypodium obtusum Spreng. Anleit. 3: 92. 1904. 

 Woodsia obtusa Torr. Cat. PI. in Geol. Rep. N. Y. 195. 

 1840. 



Rootstock short, creeping, with relatively few 

 leaves. Stipes not jointed, straw-colored, chaffy, 

 3'-6' long; blades broadly lanceolate, 6'-is' long, 

 minutely glandular-puberulent, nearly or quite 2-pin- 

 nate ; pinnae rather remote, triangular-ovate or 

 oblong, pinnately parted into oblong obtuse crenate- 

 dentate segments, or usually pinnate, the lower pin- 

 nules free and parted nearly to the midveins; sori 

 nearer the margin than the midveins; indusia con- 

 spicuous, at first enclosing the sporanges, at length 

 splitting into several broad jagged spreading lobes. 



On rocks, Nova Scotia and Maine to Wisconsin and 

 south to Georgia, Alabama, and Texas. Also in Alaska 

 and British Columbia. Variable. Ascends to 2200 ft. 

 in Virginia. 



4. DENNSTAEDTIA Bernh. Schrad. . Journ. Bot. i8oo 2 : 124. 1801. 

 [DICKSONIA in part of some authors, not L'Her. 1788.] 



Mostly medium-sized ferns, with slender wide-creeping hairy rootstocks and scattered 

 2~3-pinnate erect leaves, 2-6 high. Sori marginal, terminal upon the free veinlets, the 

 sporanges clustered upon a very small receptacle within a special cup-shaped indusium formed 

 in part of the more or less modified reflexed segment of the leaf-margin. [Name in honor 

 of August Wilhelm Dennstaedt.] 



About 50 species mainly of tropical and subtropical regions. Type species : D. flaccida 

 (Forst.) Bernh. 



i. Dennstaedtia punctilobula (Michx.) Moore. Hay-scented Fern. Fig. 29. 



Nephrodium punctilobulum Michx. Fl. Bor. Am. 2 : 268. 



1803. 



Dicksonia pilosiuscula Willd. Enum. 1076. 1809. 

 Dicksonia punctilobula A. Gray, Man. 628. 1848. 

 Dennstaedtia punctilobula Moore, Ind. Fil. xcvii. 1857. 



Rootstock slender, extensively creeping, not chaffy. 

 Stipes stout, chaffless, usually castaneous at the base; 

 blade^ i-3 long, s'-o/ wide, ovate-lanceolate to 

 deltoid-lanceolate, acute or acuminate, frequently 

 long-attenuate, usually 3-pinnatifid, thin and delicate, 

 the rachis and under surface minutely glandular and 

 pubescent; pinnae numerous, lanceolate, the seg- 

 ments ovate to oblong, close and deeply lobed, the 

 margins with oblique rounded teeth ; sori minute, 

 each on a recurved tooth, usually one at the upper 

 margin of each lobe ; sporanges few, borne within 

 the delicate cup-shaped indusium. 



In various situations, most abundant on open hill- 

 sides, Nova Scotia and New Brunswick to Ontario and 

 Minnesota, south to Georgia, Alabama and Missouri. 

 Ascends to 5600 ft. in Virginia. Aug. Called also 

 Fine-haired-fern, Hairy dicksonia, Boulder-fern. 



5. FILIX Adans. Fam. PI. 2 : 20, 558. 1763. 

 [CYSTOPTERIS Bernh. Schrad. Neues Journ. Bot. i 2 : 26. 1806.] 



Delicate rock ferns with slender stipes, 2-4-pinnate blades, and roundish sori borne on 

 the backs of the veins. Indusium membranous, hood-like, attached by a broad base on its 

 inner side and partly under the sorus, early thrust back by the expanding sporanges and at 

 least partly concealed by them, withering, the sori thus appearing naked with age. Veins free. 



About 10 species mainly natives of temperate regions; the following in North America. Type 

 species : Polypodium bulbiferum L. 

 Blades lanceolate, broadly lanceolate, or narrowly deltoid-lanceolate, 2-3-pinnate. 



Blades broadest at base, long-tapering, bearing bulblets beneath. i. F. bulbifera. 



Blades scarcely broader at base, short-pointed ; no bulblets. 2. F. fragilis. 



Blades deltoid-ovate, 3-4-pinnate. 3. F. montana. 



