F. Brittoni/e a. W. Evans. {F. dilatata of Gray's Man., 6th Ed.). In 

 wide tufts on rocks and trees. Leaves imbricated, strongly cordate at base. 

 Lobule close to stem, inflated in outer and upper part, but compressed at 

 base. Underleaves distant, roundish, bifid i^, "irregularly dentate or cren- 

 ate on the sides above the middle." Perianth obovate, truncate, with long 

 slender beak, compressed at sides, tuberculate especially upon the several 

 ridges. New York, Conn, Ohio, Penn., &Virginia. 



F. ViRGiNiCA Gottsche. (i^ saxicola Aust.). Plants green, varying to 

 brownish, closely growing on trees or rarely on rocks. Lobule inflated 

 throughout, about ^ its width from stem. " Underleaves distant, rhombic 

 ovate, bifid ^, entire or rarely unidentate at the sides." Perianth obovate, 

 abruptly narrowed into a short, broad beak ; distinctly keeled on the lower 

 side, with two or more supplementary ridges, tuberculate. This species re- 

 sembles T. Eboracensis, but is rare in the North and common in the 

 South, while just the opposite is true of the other species. The main diGEer- 

 ences lie in the perianths. Canada to the Gulf. Common South. 



F. Eboracensis Gottsche. Green or brown, usually on trees but some- 

 times on rocks. Leaves imbricate. Lobule galeate, truncate at base, ]4, its 

 width from stem. Underleaves as in F. Virginica, Perianth obovate, 

 somewhat compressed, with short, broad beak, distinct sometimes two- 

 angled keel on the underside, smooth, no supplementary ridges. Very com- 

 mon in the North. 



F. PLANA Sulliv. Grows on shaded rocks in wide tufts, usually green- 

 ish. Leaves cordate at base, decurved at rounded apex. Lobule close 

 to stem, inflated especially in upper and outer parts. "Underleaves 

 distant, reniform, cordate at base,"" bifid with obtuse lobes and 

 sinus. Perianth smooth, with short, broad beak. The species is uncommon, 

 but has been found in Connecticut, New York, New Jersey and Tennessee. 



F. AsAGRAYANA Mout. In tufts on rocks, sometimes on trees, usually 

 reddish brown. Lobule its width from stem, clavate or elongated obovoid. 

 Underleaves distant, round-ovate, bifid a little less than usually plane, 

 rarely reflexed at apex. Leaves with a long distinct median line of discol- 

 ored cells. Perianth oval or obovate, with short beak, compressed on the 

 sides, smooth. Common East, especially in the mountains. 



F. Tamarisci (L.) Dumort. In depressed tufts, brown, rarely greenish, 

 on rocks and trees. Leaves cordate at base, with decurved apex sometimes 

 acute, with indistint row of discolored cells. Lobule short clavate, con- 

 tracted toward base. Underleaves distant, round, bifid ^, with broad sinus, 

 reflexed at apex and sides, crispate-auriculate at base. Perianth oblong, 

 keeled on underside, short beaked, smooth. Rare and sterile, the under- 

 leaves serving as a guide to identification. 



F. Selwyniana Pearson. On trees, small, reddish-brown or purple. 

 Lobule close to stem and parallel to it, short clavate. Underleaves distant, 

 bifid entire or unidentate at sides. Leaves with line of discolored cells. 

 Perianth obcuneate, compressed, keeled on underside, with short broad beak, 

 minutely setulose at mouth. Rare. Collected in Ohio and Canada. 



