POLYPODIACEAE 17 



recurved, sometimes unequally hippocrepiform, rarely roundish. Indusia shaped like 

 the sorus and attached as in Asplenium, or rarely vestigial and concealed. 



Blades bipinnatifid; segments lightly crenate-serrate. 1. A. thelypteroides. 



Blades bipinnate; pinnules variously incised or deeply serrate. 2. ^4. Filix-foemina. 



1. Athyrium thelypteroides (Michx.) Desv. Eootstock sinuous. Petioles 2-3 



dm. long, straw-colored; leaf -blades lanceolate, 3-9 dm. long, acute or acuminate, 



narrowed to the base, 2-pinnatifid ; leaflets linear-lanceolate, sessile, acuminate, 



deeply pinnatifid into numerous oblong obtuse or subacute, slightly crenate segments: 



sori crowded, slightly curved, or straight, the lower ones often appearing to be double: 



indusium light-colored, lustrous when young. [Asplenium acrostichoides Sw.] 



In rich moist woods. Nova Scotia to Minnesota, south to Georgia and Louisiana. Also 

 in Asia. SIL^'ERY Spleenwort. 



2. Athyrium Filix-fofemina (L.) Roth. Eootstock relatively slender. Petioles 

 tufted, 0.5-2.5 dm. long, straw-colored, brownish or reddish; leaf -blades broadly 

 oblong-ovate to oblong-lanceolate, acuminate, 3-9 dm. long, 2-pinnate; leaflets lanceo- 

 late, acuminate, short-stalked or the upper ones sessile, 1-2 dm. long, the ultimate 

 divisions oblong-lanceolate, incised or serrate, their lobes or teeth often again toothed: 

 sori short, the indusia straight or curved. [Asple7iiu7n Filix-foemina (L.) Bernh.] 



In wet woods and thickets. Nova Scotia to Alaslia, south to Florida, Louisiana and 

 Arizona. Also in Europe and Asia. Very variable. Lady Fern. 



19. PHYLLITIS Ludwig. 

 Medium-sized ferns with oblong or strap-shaped mostly entire leaf-blades. Sori 

 li^' ''ar, elongated, almost at right angles to the midrib and contiguous in pairs, one 

 oi-'the upper side of a veinlet, the other on the lower side of the next contiguous 

 veinlet, each with a narrow laterally attached indusium meeting that of the other, 

 the double sorus thus appearing to have a common indusium opening longitudinally 

 along its middle. [Scolopendi'ium Adans.] 



1. Phyllitis Scolop6ndrluin (L.) Newman. Eootstocks short, erect or ascend- 

 ing, chaffy with light brown scales, the leaves in a spreading crown. Petioles 5-15 

 cm. long, deeiduously fibrillose-chaffy ; leaf -blades simple, bright green, firm, 2-4.5 

 dm. long, cordate or auricled at the base, entire or lightly sinuate; veins free, usually 

 once forked near the midrib: sori distinct, 4-15 mm. long. [S. vulgare J. E. Smith.] 



Shaded limestone cliffs and depressions. New Brunswick to Ontario and New York, and 

 in Tennessee. Also in Europe, Asia and Africa. Hart's Tongue. 



20. CAMPTOSORUS Link. 



Slender plants, with narrow tapering simple entire or lightly sinuate leaf -blades. 

 Sori linear or oblong, several times longer than broad, irregularly scattered on either 

 side of the reticulate veins or sometimes crossing them, partly parallel to the midrib 

 and partly oblique, the outer ones sometimes approximate in pairs. Indusium thin, 



1. Camptosorus rhizophyllus (L.) Link. Eootstock short, chaffy. Petioles 

 light green, 2.5-15 cm. long, tufted, spreading ; leaf -blades thin or somewhat leathery, 

 lanceolate, simple, 10-25 cm. long, the base usually cordate or auriculate, sometimes 

 hastate, the basal auricles occasionally much elongated, the apex of the blade long- 

 attenuate and usually filiform, rooting at the tip and giving rise to a new plant. 



On rocks, preferring limestone, Quebec to Ontario and Minnesota, south to Georgia, 

 Alabama and Kansas. Walking Leaf. Walking Fern. 



21. STENOCHLAENA J. Sm. 



Mainly epiphytes of tropical regions. Eootstocks wide-creeping, usually scandent, 

 woody. Leaves mostly once-pinnate, strongly dimorphous, the fertile leaflets narrow. 

 Sporanges non-indusiate, confluent, at maturity covering the under surface. 



1. Stenochlaena Kunzeana (Presl) Underw. Eootstock scandent, flattened, 

 with a few thin ovate-lanceolate scales. Leaves alternate, 3.5-6 dm. long; blades 

 oblanceolate, 2-4 dm. long, 1-2 dm. broad; leaflets numerous, linear-lanceolate, 6-12 

 cm. long, 10-12 mm. broad, narrowly cuneate at the base, irregularly erose-dentate, 

 the lower ones gradually much reduced. Fertile leaflets less than 5 mm. broad. 



In hammocks, southern peninsular Florida. Also in Cuba and Santo Domingo. 

 2 



