155. Cetraria] 39. PARMELIACEAE 337 



undulate, curled, crenate, white-sorediate ; pale below with occasional scattered 

 rhizoids; apothecia rare, small, 1-2.5 mm. across, marginal, sessile, the disk con- 

 cave to convex, of same color as thallus to darker, the exciple entire to crenulate; 

 spores ellipsoid, 6-9 X 3-6 jx. 



On fences and trees, New England, California, Oregon, and Washington. 



11. Cetraria fahlunensis (L.) Schaer., Lich. Helv. Spic. 5:255-57. 1833. 

 Lichen fahlunensis L., Sp. PI. 1143. 1753. 



Thallus small to middle-sized, foliose, many-cleft, irregularly divided, dusky 

 brown to blackening, the lobes laciniate, overlapping, the margins entire to crenate; 

 smooth to wrinkled and blackening below with scattered rhizoids; apothecia small 

 to middle-sized, 2-9 mm. across, marginal, the disk concave to convex, becoming 

 irregular and dilated, chestnut-brown, the exciple wrinkled, crenulate; spores ellip- 

 soid, 5-11 X 3.5-7 p. 



On alpine rocks, New England and New Jersey. 



12. Cetraria ciliaris Ach., Lich. Univ. 508. 1810. 



C. ciliaris var. montana Tuck. Nephromopsis ciliaris (Ach.) Hue. 



Thallus middle-sized, foliose, greenish gray to brownish, wavy to laciniately 

 lobed, the lobes often narrow and many-cleft, more or less lacunose, crowded, as- 

 cending, the margins crenate, bearing scattered cilia; of same color to paler below, 

 pitted-lacunose, bearing scattered to frequent rhizoids; apothecia small to large, 

 1.5-12 mm. across, marginal, sessile, the disk concave to irregular, pale to chestnut- 

 brown, the exciple crenulate; spores spherical to subspherical, 5-7 X 4-5 /x. 



On trees and old wood, from New England westward to the Pacific Coast. 



13. Cetraria platyphylla Tuck., Syn. N. A. Lich. 1:34,35. 1882. 



Platysma orbatum Nyl., Flora 52:442. 1869 with insufficient diagnosis. Ne- 

 phromopsis platyphylla (Tuck.) Herre. 



Thallus small to middle-sized, foliose, rigid, greenish brown, irregularly cleft, 

 the lobes round to irregular, reticulate-lacunose, tuberculate, the margins entire 

 to crenulate or jagged, sometimes crinkled; apothecia marginal, middle-sized, 

 1-9 mm. across, sessile, the disk concave to irregular, pale to dark chestnut-brown, 

 shining, the exciple crenulate or tuberculate; spores subspherical to short-ellipsoid, 

 4.5-7 X 4-6/*. 



On trees and dead limbs, Montana, Washington, Oregon, and California. 



14. Cetraria cucullata (Bell.) Ach., Meth. Lich. 293. 1803. 

 Lichen cucullatus Bell., Osserv. Bot. 154. 1788. 



Thallus small to middle-sized, fruticose, erect, tufted, greenish gray to straw- 

 colored or brownish, the lobes narrow, long, branched, smooth, more or less lacu- 

 nose, flattened to rolled or tubular, the margins undulate, entire to crenate; 

 apothecia middle-sized, 6-9 mm. across, adnate to the lower side of the lobes, the 

 disk often dilated, chestnut-brown, the exciple thin, entire; spores ellipsoid, 7—10 X 

 3-4 fi. 



On soil, in alpine areas, New England and the Rocky Mountains. 



15. Cetraria nivalis (L.) Ach., Meth. Lich. 294,295. 1803. 

 Lichen nivale L., Sp. PI. 1145. 1753. 



Thallus small to middle-sized, erect, rigid, tufted, straw-colored to yellowish 

 white or yellowish toward the base, much and deeply lobed, the lobes narrow or 

 rather broad, more or less widely channeled or reticulately pitted, many-cleft 

 above, the margins irregularly dentate; apothecia small to middle-sized, 2-5 mm. 

 across, adnate, subterminal, the disk flat, becoming irregular, yellowish flesh-colored 

 to brownish, the exciple thin, irregular, crenulate; spores ellipsoid, 7-9 X 3-5 fi. 



On soil, New England, Montana, Wyoming, and Colorado. 



