113. Psoroma ] 30. PANNARIACEAE 177 



6. Pannaria rubiginosa (Thunb.) Del., in Bory, Diet. Class. Hist. Nat. 13:20. 



1828. 

 Lichen rubiginosus Thunb., in Ach., Lich. Suec. Prod. 99. 1798. 

 Thallus round, plainly foliose, middle-sized to large, smooth to minutely granu- 

 lose, greenish gray to ashy, yellowish, or lead-colored, the lobes elongated, more or 

 less imbricated, deeply waved or divided toward the raised and crenate margins; 

 lighter to darkening below and covered with light to darkening rhizoids upon an 

 obscure bluish black hypothallus; apothecia small to middle-sized, O.S-2.5 mm. 

 across, sessile, the disk flat to slightly concave, red to reddish brown, the exciple 

 thick, crenulate, colored like the thallus; hypothecium brownish; spores ellipsoid- 

 pointed, 14-26 X 6-11 fi. 



On trees, throughout the United States. 

 var. lanuginosa (Hoffm.) Zahlbr., Cat. Lich. Univ. 3:258. 1925. 

 Lichen lanuginosus Hoffm., Enum. Lich. 82. pi. 10, f. 4. 1784. Parmelia cono- 

 plea (Pers.) Ach. P.conoplea (Pers.) Bory. P. rubiginosa var. conoplea 

 (Pers.) Koerb. 

 Thallus bluish gray to darker, densely grayish sorediate, passing toward the 

 center into a continuous crust; apothecia often without thalloid exciple. 



On trees, New England, North Carolina, West Virginia, Minnesota, and Cali- 

 fornia. 



7. Pannaria lurida (Mont.) Nyl., Mem. Soc. Sci. Nat. Cherb. 5:109. 1857. 



Collema luridum Mont., Ann. Sci. Nat. Bot. II. 18:266. 1842. Parmelia Rus- 

 sellii Tuck. Physma luridum (Mont.) Tuck. 



Thallus middle-sized to large, wrinkled and powdery, greenish gray to yellowish 

 or bluish gray, the lobes irregular, imbricated, with crenate or cut margins; pale 

 below and covered more or less with pale or blackening rhizoids; apothecia small 

 to middle-sized, 0.8-2.5 mm. across, adnate, the disk flat to convex, reddish brown 

 to brownish black, the exciple thin, colored like the thallus, wrinkled to crenate; 

 hypothecium hyaline to slightly brownish; spores ellipsoid to ellipsoid-pointed, 

 13-18 X 7-9.5 fi. 



On trees and rocks, from Maine to Florida, and westward to Illinois and 

 Missouri. 



OTHER SPECIES REPORTED 



Pannaria Halei Tuck. — Louisiana. 

 Pannaria melamphylla Tuck. — Vermont. 



113. Psoroma Nyl., Mem. Soc. Sci. Nat. Cherb. 3:175. 1855. 



Thallus squamulose, more or less irregular, commonly smooth, usually attached 

 to the substratum by few rhizoids, differentiated into a well-developed cellular 

 cortex of several rows of horizontal plectenchyma or rarely of irregular interwoven 

 hyphae, more or less indistinct algal and medullary layers and a thin lower cortex 

 composed of densely interwoven hyphae; apothecia middle-sized to large, adnate 

 to sessile, the disk concave to flat, red to brown, the exciple colored like the thallus; 

 hypothecium and hymenium hyaline; paraphyses unbranched, more or less co- 

 herent; asci clavate; spores 8, hyaline, ellipsoid to ovoid-ellipsoid or spherical, 

 non-septate. 



The algal host is Dactylococcus (?). 



1. Psoroma hypnorum (Vahl.) S. F. Gray, Nat. Arr. Brit. PI. 1:445. 1821. 



Lichen hypnorum Vahl., Icon. PI. Dan. fasc. 16. pi. 956. 1787. Parmelia hyp- 

 norum (Vahl.) Ach. Pannaria hypnonim (Vahl.) Koerb. 



Thallus composed of minute, round, crenate, and imbricate, granulose, ascend- 

 ing, yellowish to reddish brown or finally grayish squamules; pale below; apothe- 

 cia middle-sized to large, 1.5-5 mm. across, sessile, the disk concave to flat, reddish 



