136 21. DIPLOSCHISTACEAE [77. Urceolaria 



7. Urceolaria Ach.. Meth. Lich. 141. 1803. 



Thallus crustose, thick, areolate or warty, differentiated into a poorly developed 

 upper cortex of entangled hyphae, more or less distinct algal and medullary layers, 

 attached to the substratum by numerous hyphal rhizoids; apothecia minute to 

 small or middle-sized, immersed to adnate, the disk closed to open, more or less 

 concave, the exciple thick, colored like the disk, irregular, usually surrounded by 

 a thin thalloid one; hypothecium brownish to brown; hymenium hyaline or brown- 

 ish above; paraphyses sometimes branched toward the apices; asci cylindrico- 

 clavate; spores 2-8, brown, ellipsoid to oblong-ellipsoid, transversely and 

 longitudinally septate. 



The algal host is Protococcus. 



A. Not parasitic on lichens 



B. Spores not more than 35 fi in length 



C. Proper exciple thick, radiately striate 3. U. actinostoma 



C. Proper exciple thin, minutely toothed 



D. On soil and rocks among moss 1. U. scruposa bryophila 



D. On soil and rocks, but not among moss 1. U. scruposa 



B. Spores 31-50 /j, in length .2. U. albissima 



A. Parasitic on lichens 1. U. scruposa parasitica 



1. Urceolaria scruposa (Schreb.) Ach., Lich. Suec. 32. 1798. 



Lichen scruposus Schreb., Spic. Fl. Lips. 133. 1771. Parmelia scruposa 

 (Schreb.) Hepp. Diploschistes scruposus (Schreb.) Norm. U . ochroleuca 

 Tuck. 



Thallus thin to thick, composed of minute to small, wartlike, uneven, continu- 

 ous and crowded, greenish gray to ashy white areoles; apothecia small to middle- 

 sized, 0.3-1 mm. across, commonly immersed to becoming adnate, the disk deeply 

 concave, black or grayish pruinose, the proper exciple thin, black, minutely toothed, 

 surrounded by a thick, swollen, sometimes crenate, more or less disappearing, 

 thalloid one; spores 4-8, brownish to brown, oblong-ellipsoid, S-7-septate trans- 

 versely and 1-3-septate longitudinally, 20-34 X 10-15 jx. 



On rocks and rarely on trees and old wood, throughout the United States. 



var. bryophila (Ehrh.) Ach., Meth. Lich. 148. 1803. 



Lichen bryophilus Ehrh., PI. Crypt. Exsicc. no. 236. 1774. Parmelia scruposa 



var. bryophila (Ehrh.) Hepp. Diploschistes bryophilus (Ehrh.) Zahlbr. 



Thallus thin, smooth to slightly rough, becoming areolate, ashy gray to whitish; 



apothecia small, 0.3-0.6 mm. across; spores 8, brownish to brown, ellipsoid to 



oblong-ellipsoid, 5-7-septate transversely and 1-2-septate longitudinally, 26-28 X 



10-12 fi. 



On soil and rock among moss and species of Cladonia, West Virginia, Colorado, 

 and California. 



var. parasitica (Sommerf.) Tuck., Syn. N. A. Lich. 1:222. 1882. 

 Lecanora scruposa var. parasitica Sommerf., Suppl. Flor. Lap. 100. 1826. 



Diploschistes scruposus var. parasiticus (Sommerf.) Zahlbr. 

 Thallus very thin and often disappearing; apothecia small, 0.3-0.6 mm. across; 

 spores 8, oblong-ellipsoid, 5- rarely 7-septate transversely and 1- rarely 2-septate 

 longitudinally, 18-21 X 7-9//.. 



On the thallus of species of Cladonia, Massachusetts, Ohio, and South Dakota. 



2. Urceolaria albissima (Ach.) Fink n. comb. 



U. scruposa var. albissima Ach., Meth. Lich. 147. 1803. U. gypsacea Ach. 

 U. scruposa var. gypsacea (Ach.) Koerb. Diploschistes gypsaceus (Ach.) 

 Zahlbr. Diploschistes albissimus (Ach.) Dalla Torre & Sarnth. 

 Thallus thin to thick, continuous, wrinkled, uneven, minutely areolate, becom- 

 ing powdery, ashy to whitish; apothecia small to middle-sized, 0.4-1 mm. across, 

 immersed to becoming adnate, the disk deeply concave to concave, black or gray- 

 ish pruinose, the proper exciple thin, black, somewhat wrinkled, surrounded by 



