144 LICHENS OF THE STATE OF WASHINGTON 



habitat. C. arhorialis grows on wood, C. islandica on soil ; also by the lack 

 of color change of the thallus with IKI. 



13. Cetraria Merrillii DR. Arkiv for Bot. 20, A, No. 11 :42. 1926. 

 Cetraria californica Merrill, Bryol., 13:28. 1910. (Not Tuck.) 



Thallus greenish-black, fuscous-black (R), or black, foliose or sub- 

 fruticose, ascending or erect, caepsitose, lobes rather narrow, compressed, 

 lacunose, margins deeply cut into fingerlike lobules, tips acute ; below paler. 

 Apothecia abundant, marginal or submarginal, 1-6 mm. in diameter, sessile; 

 disk dark brown or black, concave to flat ; thalline margin crenulate or 

 dentate; spores hyaline, ellipsoid, nonseptate, 5.0-8.5 x 3.0-4.0 /x. 



On twigs: Yakima Co.: Deadhorse Hill, 4000 ft., 1931, 961; Lodge 

 Pole Pine Camp, 3500 ft., 1940, 3303; Rattlesnake Canyon, 2000 ft., 1931, 

 1544. Ferry Co. : Mt. Gibraltar, 3100 ft., 1940, 3150. 



A distinctive Cetraria, although rather small, 



14. Cetraria nivalis (L.) Ach. Meth. Lich. 294. 1803. 

 Lichen nivalis Linn. Sp. PI. 1145. 1753. 



Thallus pale yellow, maize yellow (R), cream color (R), Naples yellow 

 (R), mustard yellow (R), or bright yellow, fruticose or subfruticose, 

 reticulate-lacunose, often channeled, or smooth, usually dull, much divided, 

 lobes deeply laciniate, margins irregular, dentate with truncate points ; 

 below slightly darker and duller. Apothecia rather rare, usually terminal, 

 2-12 mm. in diameter, adnate to the under surface of the lobe; disk fawn 

 color (R) or brown to pale brownish pink, flat becoming uneven; thalline 

 margin crenulate; spores hyaline, ellipsoid, 7.0-10.0 x 3.0-5.0 fi. 



On the earth in alpine regions : Jefferson Co. : Olympic Mountains, 

 6000 ft, 1918, /. M. Grant (F). 



This beautiful, yellow, somewhat leaf-like lichen is easily recognized. 

 Rather strange that it has not been collected in other mountainous regions 

 of the state. 



56. Nephromopsis Miill. Arg. Flora 74:374. 1891. 



Thallus much like Cetraria but distinguished from it by the apothecia, 

 which originate on the lower side, but by the twisting and turning of the 

 lobes are brought on to the upper surface, prominent tubercules scattered 

 on the lobes or confined to the margins, or in both places; below smooth, 

 lacunose, or wrinkled, rhizoids scarce or more abundant. Apothecia medium 

 sized, round, adnate or sessile, terminal or marginal ; disk some shade of 

 brown; asci 8-spored; spores hyaline, nonseptate. 



A. Thallus some shade of yellow 2. A^. pallidula 



A. Thallus not yellow. 



B. Lobes narrow, much branched, olive brown or brown 1. N. ciliaris 



B. Lobes broad, not much branched, dark brown 3. N. platyphylla 



