58 Purple Cliff-Brake 
est, often elongate, often connate at base with segment next 
below on one or both sides: margins thin, whitish, crenulate, 
and very minutely and obscurely denticulate: upper surface of 
ultimate divisions deep bluish-green, glabrous, lower surface 
pale, minutely paleaceous along midveins: texture coriaceous: 
rachises and footstocks of ultimate divisions purplish-ebeneous 
or blackish-red, usually paleaceous. 
Venation pinnate, obscure, free or with occasional areole: 
primary branches of midveins once to three times or the basal 
four times, those above the basal mostly twice forked. 
Sori intramarginal on upper part of veins, becoming conflu- 
ent laterally: indusia formed of reflexed margin of ultimate 
divisions of leaf, continuous around sides and apex of division 
or interrupted at apex: at margin minutely denticulate or undu- 
late, often finely fluted. 
Spores obscurely tetrahedral, or trivittate. 
Habitat. Dry rocks, especially limestone, exposed to the sun 
or partly shaded. Often near the tops of cliffs, projecting in 
masses from cracks in the rock or growing in partly caked sand 
on the ledges; or on surface rock on hillsides. 
Range. Massachusetts, Vermont, and Ontario to British 
Columbia and Mackenzie, south to Georgia, Mississippi, Texas, 
Arizona, and California. 
Pellea atropurpurea-Linnezus-Link, Fil. Sp. Hort. Berol. 59. 184r. 
Pteris atropurpurea Linnzus, Sp. Pl. 1076. 1753. 
THE young leaf-blade of Pellea atropurpurea is simple and 
roundish or reniform at first (Pl. VIII, Fig.1). It then elon- 
gates and two lobes develop, either simultaneously or succes- 
sively, at its base (Pl. VIII, Fig. 2-5). These lobes are the blade’s 
