LICHENS OF THE STATE OF WASHINGTON 143 



On soil: Ferry Co.: Republic, 2650 ft., 1912, Foster 2283 (F). 

 Rare, usually in the mountains. It can easily be distinguished from 

 C. islandica. 



II. Cetrariaislandica (L.) Ach. Meth. Lich. 293. 1803. 

 Lichen islandicus Linn. Sp. PI. 1145. 1753. 



Thallus various shades of brown, light brownish-olive (R), or sepia 

 (R), sometimes reddish towards the base, foliose or fruticose, tufted, erect, 

 rigid, stiff, lobes narrow, branched dichotomously or irregularly, smooth, 

 shiny, sometimes lacunose or channeled, flat or often rolled into a tube, 

 margins involute, abundantly ciliate-spinulose from the tips to the base; 

 below darker or sometimes lighter, with sunken, round, sorediate areas 

 usually abundant. Apothecia usually terminal, 1-10 mm. in diameter, adnate 

 to the upper surface of the lobe ; disk chestnut-brown (R) or darker, concave 

 to convex, surface often uneven ; thalline margin thin, entire or crenulate, 

 soon disappearing; spores hyahne, ellipsoid, nonseptate, 6.6-9.9 x 3.3-5.0 {i. 

 Thallus blue with IKI. 



On soil : Whatcom Co. : Ruth Mountain, 5500 ft., 1928, L. Sunqnist 

 1890 (W). Herre (1917) reports it from Whatcom Co.: Mt. Baker. 



An alpine species that can be distinguished easily by the abundant cili- 

 ate-spinulose margins and its habitat, always grows on soil. 



12, Cetraria arborialis (Merrill) Howard comb. nov. 



Cetraria islandica mod. arborialis Merrill, Bryol. 9 :4. 1906. 



Thallus various shades of brown, sepia (R), light brownish olive (R), 

 light grape green (R), grape green (R), or yellowish glaucous (R), 

 foliose or fruticose, cartilagenous, lobes elongated, channeled or almost 

 flat, smooth, dull or shiny, irregularly dichotomously branched, often form- 

 ing matted masses, margins entire, undulate or crenate, here and there 

 ciliate-spinulose, tips very rarely spinulose ; below paler, slightly lacunose. 

 Apothecia usually terminal, 3-6 mm. in diameter, adnate to upper surface ; 

 disk pale brown, concave to convex, surface becoming uneven; thalline 

 margin thin and slightly crenulate ; spores hyaline, globose, 3-4 fj. in diam- 

 eter. Thallus shows no color change with IKI. 



On shrubs, living or dead, usually a species of Vaccinium : Pierce Co. : 

 Mt. Rainier, Berkeley Park, 6000 ft., 1931, 610; Mowich Lake Trail, 3500 

 ft., 1940, 3062; trail to Seattle Park, 4000 ft., 1940, 3059. Yakima Co. : 

 Dewey Lake, 4700 ft., 1940, 3354. Whatcom Co. : Ruth Mountain, 5500 ft., 

 1928, L. Sunquist 1890a (W). Olympic Mountains on low shrubs, 5000 ft., 

 1895, C. V. Piper 528 (C), this specimen determined as Cetraria islandica 

 mod. arborialis Merrill, Fide R. H. Howe, Jr. Jefferson Co.: Olympic 

 Mountains, Queets River Valley, 5000 ft., 1907, Frye 14 (W), this speci- 

 men determined as Cetraria islandica var. arboricoline Tuck, by G. K. Mer- 

 rill. Clallam Co.: Olympic Hot Springs on Vaccinium sp., 1914, Foster 

 (W), this specimen determined as Cetraria islandica. 



An alpine species, easily separated from C. islandica by the difference in 



