338 39. PARMELIACEAE [ 155. Cetraria 



16. Cetraria calif ornica Tuck., Am. Journ. Sci. II. 28:203. 1859. 



Alectoria cetrariza Nyl. Coelocalon calif omicwn (Tuck.) Howe. Alectoria cali- 

 f ornica (Tuck.) Merrill. 



Thallus small, fruticose, ascending, tufted, greenish brown to black, much 

 branched, the branches spreading, smooth to canalled or lacunose, flat and narrow- 

 linear to compressed-round, the tips much divided, the margins sometimes crenu- 

 late or jagged; paler below; apothecia small to middle-sized, 1.5-6 mm. across, 

 terminal, sessile, the disk flat to convex or irregular, dark green to black, rarely 

 shining, the exciple nearly entire to toothed or fringed ; spores ellipsoid, 6-9 X 

 3—5 fi. 



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



17. Cetraria islandica (L.) Ach., Meth. Lich. 293. 1803. 



Lichen islandicus L., Sp. PI. 1145. 1753. C. islandica var. crispa Ach. C. islan- 

 dica var. platyna Ach. C. islandica var. arborialis Merrill. 



Thallus small to middle-sized, subfoliose or fruticose, tufted, rigid, shining, 

 pale to dusky chestnut-brown or olive-green, sometimes reddish toward the base, 

 many-lobed, the lobes very narrow and elongated to shorter and wide, subdichot- 

 omously to irregularly branched, smooth to lacunose, flattened to rolled, often 

 into a closed tube, the margins entire to thickly spinulose; paler below, and often 

 more or less covered with impressed white soredia; apothecia small to middle- 

 sized, 1.5-14 mm. across, sessile at tips of lobes, the disk concave to convex or 

 irregular, chestnut-brown to darker, the exciple thin, entire to crenulate; spores 

 oblong-ellipsoid, 6-10 X 3.5-5 /*. 



On soil and rarely on twigs, from New England to the Carolinas, and west- 

 ward to the Pacific Coast (more common in alpine areas). 



18. Cetraria hiascens (E. Fries) T. Fries, Lich. Scand. 98,99. 1871. 



C. acideata var. hiascens E. Fries, Lich. Eur. 36. 1831. C. islandica var. Delisaei 

 Bory. 



Thallus small to middle-sized, fruticose, erect, densely tufted, rigid, pale to 

 dusky brown, many-lobed, the lobes narrow, elongated, subdichotomously much- 

 branched, especially toward the apices, smooth, often lacunose, flattened to rolled, 

 the margins entire toward the base, crenulate to spinulose toward the apices; apo- 

 thecia rare, small to middle-sized, 1-7 mm. across, adnate, marginal or terminal, 

 the disk concave, pale to chestnut-brown, the exciple entire to crenulate; spores 

 ellipsoid, 6-11 X 3.5-6 fx. 



On soil and rocks, New Hampshire, Delaware, the Carolinas, Rocky Moun- 

 tains, Oregon, and Washington (usually in alpine areas). 



19. Cetraria aculeata (Schreb.) E. Fries, Lich. Eur. 35,36. 1831. 



Lichen aculeatus Schreb., Spic. Fl. Lips. 125. 1771. C. aculeata var. alpina 

 Schaer. 



Thallus small to middle-sized or larger, fruticose, erect, tufted, rigid, hollow, 

 round to compressed, angulose and more or less contorted, often shining, pale to 

 blackening chestnut-brown, much branched, the branches spreading and more or 

 less beset with spicules especially toward the apices; apothecia small to middle- 

 sized, 2-7 mm. across, subterminal, the disk concave to convex and irregular, 

 chestnut-brown, the exciple toothed and spinous ; spores ellipsoid, 6-9 X 3-4 //.. 



On soil and over exposed rocks, in alpine areas, from New England westward 

 to Wyoming and Washington. 



20. Cetraria tristis (Web.) E. Fries, Lich. Eur. 34,35. 1831. 

 Lichen tristis Web., Spicil. 209. 1778. 



Thallus small, fruticose, tufted, very rigid, brownish black, branched, the 

 branches repeatedly divided especially toward the tips into subparallel branchlets, 

 round to compressed ; apothecia small to middle-sized, 1-5 mm. across, subterminal 



