153. Parmeliopsis ] 39. PARMELIACEAE 319 



var. effusa (Tuck.) Merrill & Burnh., Bryologist 25:73. 1922. 

 Teloschistes concolor var. effusa Tuck., Syn. N. A. Lich. 1:52. 1882. 

 Thallus reduced to granulose, more or less scattered squamules, or sometimes 

 passing into a more or less continuous powdery crust. 

 On trees, throughout the United States. 



2. Candelaria fibrosa (E. Fries) Mull. Arg., Flora 70:319. 1887. 



Parmelia fibrosa E. Fries, Syst. Orb. Veg. 1:284. 1825. Physcia candelaria var. 

 stellata Nyl. C. stellata (Nyl.) Mull. Arg. 



Thallus round to irregular and stellate, more or less irregularly lobed, the lobes 

 imbricated, smooth to rough, short and broad to more or less elongated, the mar- 

 gins repeatedly and deeply incised, yellow to rarely ashy; white below and bear- 

 ing numerous, short, white rhizoids; apothecia minute to small, 0.2-1 mm. across, 

 round, sessile, slightly constricted at the base, the disk flat, yellow, the exciple thin, 

 prominent, colored like the thallus, entire to crenulate, bearing minute fibrils be- 

 low; hypothecium hyaline; hymenium yellowish above and hyaline below; spores 

 many, hyaline, ellipsoid or ovoid-ellipsoid, straight, non-septate to 1 -septate, 

 9-12 X 4-6/*. 



On trees and rocks, from New England to South Carolina, and westward to 

 Ohio and Texas (description compiled from Zahlbruckner, who studied the original 

 specimen in Herbarium of Jean Muller of Argo). 



153. Parmeliopsis Nyl., Syn. Lich. 2:53. 1863. 



Thallus foliose, compressed, more or less irregularly lobed, differentiated into 

 an upper and lower cortex of more or less vertically extending, somewhat inter- 

 woven hyphae, and irregular algal and medullary layers; apothecia small to middle- 

 sized, sessile, the disk concave to more or less convex, usually brown, the exciple 

 colored like the thallus, becoming irregular; hypothecium hyaline to brownish; 

 hymenium hyaline or brownish above; paraphyses rarely branched; asci clavate; 

 spores 8, hyaline, subspherical to ellipsoid or broadly ellipsoid, sometimes curved, 

 non-septate. 



The algal host is Pleurococcus. 



A. Thallus bearing coralloid granules or soredia 

 B. Thallus bearing coralloid granules 



C. Granules densely crowded over the thallus except 



toward the margins 2. P. aleurites 



C. Granules scattered over the thallus 2. P. aleurites diffusa 



B. Thallus bearing soredia 



C. Thallus straw-colored to ashy white or yellowish, 

 bearing yellowish or sulphur-colored soredia 



D. Exciple crenulate 3. P.ambigua 



D. Exciple constantly powdery-sorediate 3. P. ambigua Halei 



C. Thallus whitish to ashy or ashy brown, bearing whitish 



or dirty-ashy soredia 4. P. diffusa 



A. Thallus without coralloid granules or soredia 1. P. placorodia 



1. Parmeliopsis placorodia (Ach.) Nyl., Syn. Lich. 2:55. 1860. 



Parmelia placorodia Ach., Syn. Meth. Lich. 196. 1814. Cetraria placorodia 

 (Ach.) Tuck. Cetraria aleurites var. placorodia (Ach.) Tuck. 



Thallus small, round, adnate throughout or marginally ascending, greenish gray 

 to ashy, smooth to wrinkled toward the center, the lobes more or less regularly 

 arranged, narrow, branched, the margins deeply wavy to pinnate-cleft; whitish 

 below, with scattered brownish to brown rhizoids; apothecia small to middle-sized, 

 1.5-7 mm. across, sessile, the disk concave to convex, yellowish to chestnut-brown, 

 the exciple thin, colored like the thallus, crenulate; spores subspherical to broadly 

 ellipsoid, 4.5-9 X 3.5-6 /*. 



On trees and old wood, from Massachusetts to North Carolina. 



