278 36. ACAROSPORACEAE [ 137. Thelocarpon 



C. Apothecia adnate to sessile, spores non-1-septate .... 139. Maronea 



B. Apothecia with proper exciple 138. Biatorella 



A. Horizontal thallus almost wanting 137. Thelocarpon 



137. Thelocarpon NyL, Mem. Soc. Sci. Nat. Cherb. 2:15, 338. 1854. 



Thallus rudimentary, devoid of differentiation into layers, the superficial portion 

 absent or forming a very thin crust over the substratum; apothecia minute, globose, 

 scattered or rarely aggregate, entirely covered by a thin thalloid exciple except a 

 tiny pore at the more or less depressed apex; hypothecium and hymenium hyaline; 

 paraphyses short, unbranched or branched and interwoven; asci long, more or less 

 distended toward the center; spores numerous, minute, hyaline, spherical to oblong, 

 non-septate or rarely appearing 1 -septate. 



The algal host is Pleurococcus or Protococcus. 



A. On rocks, trees, and old wood 



B. Spores not more than 8 n in length 

 C. Apothecia scattered or aggregate 



D. Spores 2.5-4 X 1.5-2 n 1. T. Laureri 



D. Spores 3.5-6 X 1.5-2.5 jit 5. T. epilithellum 



C. Apothecia scattered 



D. Spores 2-3.5 X 1-1.5 n 2. T. majusculum 



D. Spores 4-7 X2.S4)» 6. T. prasinellum 



B. Spores more than 8 fi in length 7. T. superellum 



A. On soil or dung 



B. On soil; apothecia covered by a yellowish green exciple . 3. T. intermediellum 

 B. On dung; apothecia covered by a greenish exciple 4. T. fimicola 



1. Thelocarpon Laureri (Flot.) NyL, Mem. Soc. Sci. Nat. Cherb. 3:191. 1855. 

 Sphaeropsis Laureri Flot., Bot. Zeit. 5:65. 1847. 



Thallus rudimentary, the superficial portion absent or rarely visible; apothecia 

 minute, 0.05-0.2 mm. across, globose, scattered or rarely aggregate, entirely cov- 

 ered by a thin, yellowish green, thalloid exciple except a tiny pore at the somewhat 

 depressed apex; hyaline within; paraphyses slender, short, somewhat branched; 

 asci distended toward the center; spores oblong, 2.5-4 X 1.5-2 /x. 



On old wood, Pennsylvania and Illinois (?). 



2. Thelocarpon majusculum NyL, Flora 68:300. 1885. 



Thallus rudimentary, the superficial portion absent or scarcely visible; apothecia 

 minute, 0.1-0.25 mm. across, globose, more or less scattered, entirely covered by 

 a thin, yellowish green thalloid exciple except a tiny pore at the apex; hyaline 

 within; paraphyses slender, threadlike; asci distended toward the center; spores 

 oblong-ellipsoid, 2-3.5 X 1-1.5 [x. 



On old trees and rarely on rocks, Massachusetts, Florida, Pennsylvania (?), and 

 Illinois (?). 



3. Thelocarpon intermediellum NyL, Flora 48:261. 1865. 



Thallus rudimentary, the superficial portion absent or rarely visible; apothecia 

 minute, 0.05-0.15 mm. across, globose, scattered, entirely covered by a thin, yel- 

 lowish green, thalloid exciple except a tiny black pore at the slightly depressed 

 apex; hyaline within; paraphyses absent; asci distended toward the center; spores 

 oblong, 3.5-5 X 1.5-2 p. 



On soil, Massachusetts. 



4. Thelocarpon fimicola Fink, Mycologia 14:95, 96. 1922. 



Thallus rudimentary, the superficial portion absent or rarely visible; apothecia 

 minute, 0.05-0.15 mm. across, globose, scattered, covered entirely by a thin, green- 

 ish thalloid exciple except a tiny pore at the apex; hyaline within; paraphyses 

 indistinct and disappearing; asci cylindrical to becoming distended toward the 

 center and tapering toward both ends; spores spherical to oblong, 2-4 X 1.5-2 /x. 



On cow dung, Kentucky. 



