76. Conotrema ] 21. DIPLOSCHISTACEAE 135 



75. Gyrostomum E. Fries, Syst. Orb. Veg. 268. 1825. 



Thallus crustose, smooth, rudimentary, commonly devoid of differentiation into 

 layers, attached to the substratum by hyphal rhizoids; apothecia minute to small, 

 more or less immersed to adnate or sessile, the disk concave to flat, the exciple 

 colored like the disk, elevated, surrounded by a thin, usually disappearing, thalloid 

 one; hypothecium hyaline; hymenium hyaline or brownish above; paraphyses 

 few, branched and netlike interwoven; asci clavate to inflated-clavate; spores 2-8, 

 hyaline to brown, oblong to oblong-ellipsoid, transversely and longitudinally 

 septate. 



The algal host is Trentepohlia. 



1. Gyrostomum scyphuliferum (Ach.) E. Fries, Syst. Orb. Veg. 268. 1825. 



Lecidea scyphulijera Ach., Syn. Meth. Lich. 27. 1814. 



Thallus thin, smooth to very slightly rough, greenish ashy or olive-brown to 

 lead-colored; apothecia minute to small, 0.25-0.9 mm. across, sessile, the disk 

 flat, brown, varying toward dirty blackish, the exciple elevated, colored like the 

 disk and becoming radiately striate, surrounded by a thin, disappearing, thalloid 

 one; spores oblong-ellipsoid, 5-9-septate transversely and 1-2-septate longitudinally, 

 20-40 X 10-15 (jl. 



On trees, South Carolina, Florida, Louisiana, Alabama, and Texas. 



OTHER SPECIES REPORTED 

 Gyrostomum Curtisii Tuck. — North America. 



21. DIPLOSCHISTACEAE 



Thallus crustose, rudimentary or showing more or less differentiation, attached 

 to the substratum by hyphal rhizoids; apothecia round, immersed to superficial, 

 the proper exciple well developed, usually surrounded by a heavy thalloid one. 



The algal host is Protococcus. 



A. Spores transversely septate 76. Conotrema 



A. Spores transversely and longitudinally septate 77. Urceolaria 



76. Conotrema Tuck., Syn. Lich. N. E. 86. 1848. 



Thallus rudimentary, without distinct layers, sometimes forming a poorly 

 developed, plectenchymatous layer, crustose, thin, smooth or somewhat rough, 

 attached by hyphal rhizoids; apothecia small, more or less immersed to sessile, 

 the disk concave, commonly whitish pruinose, the proper exciple blackish, sur- 

 rounded by a thin, soon disappearing, thalloid one; hypothecium and hymenium 

 hyaline; paraphyses branched toward the apices; asci cylindrical; spores 8, 

 hyaline, cylindrical, many-septate, the cells spherical. 



The algal host is Protococcus. 



1. Conotrema urceolatum (Ach.) Tuck., Syn. Lich. N. E. 86. 1848. 



Lecidea urceolata Ach., Lich. Univ. 671. 1810. 



Thallus thin, smooth to scurfy, chinky or finally areolate, ashy whitish, some- 

 times partly disappearing; apothecia small, 0.4-0.75 mm. across, partly immersed 

 to subsessile, the disk deeply concave, blackish or whitish pruinose, the proper 

 exciple blackish, at first surrounded by a thin thalloid one; spores 29-39-septate 

 100-160X3-4.5^. (Plate 4.) 



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

 Minnesota. 



