POLYPODIACEAE 11 



lated, deciduous, cuneate, the upper edge sometimes angular, broadly and often 

 deeply lobed: sori oblong or roundish. 



In sink-holes in lime-rock, central peninsular Florida. Also in tropical America. 



3. Adiantum ped^tum L. Eootstocks slender, chaffy. Leaves numerous; 



petioles 2-4.5 dm. long, dark chestnut-brown, polished and shining; blades reniform- 



orbicular, 2-4.5 cm. broad, the larger divisions 1.5-2.5 dm. long; leaflets oblong, 



triangular-oblong or the terminal one fan-shaped, all short-stalked, the upper margin 



toothed, cleft or lobed: sori linear-oblong. 



In woods, Nova Scotia and Quebec to British Columbia and Alaska, south to Georgia, 

 Mississippi, Kansas and California. Also in Asia. Maidenhair Fern. 



4. Adiantum hispidulum Sw. Eootstock slender, creeping, branched, closely 

 covered with appressed subulate castaneous scales. Leaves several; petioles 1-3 dm. 

 long, dark chestnut-brown, closely hispid; blades orbicular to rhombic, 1-2.5 

 dm. long, the two main divisions unequal, sympodially branched; leaflets short- 

 stalked, the larger ones oblong from a broadly cuneate base, the inner margin trun- 

 cate, the lower very oblique and straight nearly to the rounded apes; leaf -tissue 

 hispid below, slightly so above: sori roundish, close, extending from the upper base 

 to or around the apex; indusia reniform-orbicular, persistent. 



Escaped from cultivation, near Thomasville, Georgia ; apparently established. Native 

 of Asia and Australasia. 



11. PELLAEA Link. 

 Eock-inhabiting plants, relatively small in size, with nearly uniform 1-3-pinnate 

 leaf-blades, the petioles light- or usually dark-colored. Sori intramarginal, borne on 

 the ends of unconnected veins, at length confluent laterally in a broad submarginal 

 line. Indusium formed by the reflexed margins of fertile leaflets, these often modi- 

 fied and membranous. Cliff-brake. 



Indusium broad: leaflets often narrow. 

 Leaf-blades 1-2 pinnate. 



Leaflets obtuse or barely acute. 



Leaflets smooth or slightly fibrillose below. 1. P. atropurpurea. 



Leaflets scabrous upon both surfaces. 2. P. scabra. 



Leaflets mucronate or decidedly acute. 3. P. Wrighiiana. 



Leaf-blades 3-4-pinnate: leaflets numerous. 4. P. pulchella. 



Indusium very narrow: leaflets broad: rachis zigzag. 5. P.flexuosa. 



1. Pellaea atropurpurea (L.) Link. Eootstocks short, densely clothed with 



long-attenuate rusty scales. Leaves tufted; petioles 5-15 cm. long, dark purplish; 



blades leathery, lanceolate, deltoid-ovate, 1-3 dm. long, pinnate or 2-pinnate below; 



rachis dark-brown or purplish, smooth or fibrillose; leaflets 2.5-5 cm. long. 



On rocks, preferring limestone, Ontario to Mackenzie and British Columbia, south to 

 Georgia, Mississippi, Texas, Arizona and California. 



2. Pellaea scabra C. Chr. Leaves several; petioles slender, 5-8 cm. long, with 

 scurfy pubescence; blades oblong-lanceolate, 10-15 cm. long, 2-pinnate; leaflets del- 

 toid-lanceolate or oblong, scabrous, the basal ones often lobed. [P. aspera Baker.] 



On dry rocks, Texas and New Mexico. 



3. Pellaea "Wrlghtlana Hook. Eootstocks stout, densely chaffy. Leaves 

 crowded; petioles purplish brown, 10-15 cm. long; blades lanceolate to deltoid, 10-25 

 cm. long, 2-pinnate, or 3-foliolate toward the apex; leaflets mucronate, the fertile 

 ones with margins widely inflexed, sometimes to the midrib. 



On rocks, Colorado to Texas and California. Also in Mexico. 



4. Pellaea pulchella (Mart. & Gal.) Fee. Leaves clustered; petioles 7-16 cm. 

 long, chaffy at the base, nearly black; blades 7-18 cm. long, triangular-ovate, 4-pin- 

 nate below; leaflets numerous, oval or cordate-ovate, 2-6 mm. long, stalked, smooth. 



In dry places, western Texas and New Mexico. Also from Mexico to Chile. 



5. Pellaea flexuosa (Kaulf.) Link. Eootstocks slender. Leaves several; 

 petioles reddish, passing into the zigzag rachis, with deflected and zigzag nearly 

 smooth secondary and tertiary divisions; blades ovate-oblong, 16—75 cm. long, 2-pin- 

 nate: leaflets roundish ovate or nearly cordate-ovate, 10-20 mm. long, smooth. 



On dry rocks, Texas to California. Also in Mexico, Santo Domingo and South America. 



12. CHEILANTHES Sw. 



Small rock-inhabiting ferns, mostly with pubescent or variously scaly foliage. 

 Leaves uniform: blades much divided. Sori terminal on the veins, marginal, roundish 



