LICHENS OF THE STATE OF WASHINGTON 159 



D. Fibrils lacking or very sparse and tortuous 6. U. plicata 



D. Fibrils numerous. 



E. Cortex densely papillate, fibrils branched, white medulla show- 

 ing through cracks in the cortex, medulla shows no color 



change with KOH 2. U. ceratina 



E. Cortex sparsely papillate, fibrils rarely branched, white me- 

 dulla not showing through cracked cortex, medulla yellow 

 then turning red with KOH ; all specimens do not show this 

 color change 3. U. dasypoga 



1. Usnea cavernosa Tuck, in Agassiz, Lake Superior 171. 1850. 



Thallus greenish gray, pendulous, elongated, terete or angular, often 

 lacunose, sometimes seamed and ridged, cortex broken in partial or com- 

 plete rings, but rarely exposing the medulla, main branches like very coarse 

 hair, secondary branches finer, irregularly dichotomously branched, bearing 

 long, slender tangled fibrils. Apothecia marginal, 3-5 mm. in diameter, 

 pedicellate ; disk concolorous with the thallus or flesh colored, flat ; thalline 

 margin often bearing fibrinoid branches; spores hyahne, ovoid ellipsoid, 

 nonseptate, 9.0-11.0 x 5.5-7.0 fx. 



On trees: Reported from Washington by Fink (1935), but I have 

 never studied a specimen collected in the state. 



The terete, ridged and sometimes lacunose main branches distinguish 

 this from any other species of Usnea. 



2. Usnea ceratina Ach. Lichenogr. Univers. 619. 1810. 

 Usnea barbata var. ceratina (Ach.) Schaer. 



Thallus grayish green, honey yellow (R), or rufescent, pendulous, 

 flexible, thickly papillate, at times sorediate, cortex often broken into rings 

 exposing the white medulla, branches coarse, terete, elongated, usually 

 much divided dichotomously, thickly beset with curly fibrils that are often 

 branched. Apothecia lateral or subterminal, 2-9 mm. in diameter, pedi- 

 cellate; disk concolorous with the thallus or pale oHve-buff (R), flat; 

 thalline margin entire or bearing fibrinoid branches ; spores hyaline, ovoid 

 ellipsoid, nonseptate, 4.5-8.0 x 4.5-6.0 fi. Medulla shows no color change 

 with KOH. Plate XI, C. 



On trees: Pacific Co.: Long Beach, 1928, 2125a; Loomis Lake, 1931, 

 747. Wahkiakum Co.: Cathlamet, 1940, 2858. San Juan Co.: San Juan 

 Island, Friday Harbor, 1940, 3240. Island Co.: Whidbey Island, 1931, 

 1779. Clallam Co.: Port Angeles, 1911, Foster (F). Spokane Co., 1906, 

 /. A. Bonser (F). Clallam Co.: Sequim, 1915, /. M. Grant (F). 



3. Usnea dasypoga (Ach.) Rohl. Deutschl. Fl. 3, Abt. 2:144. 1813. 

 Usnea plicata var. dasypoga Ach., Meth. Lich. 312. 1803. 

 Usnea barbata var. dasvpoga Ach. Lichenogr. Univers. 624. 1810. 



