8. Microglaena ] 2. DERMATOCARPACEAE 37 



1. Thrombium epigaeum (Pers.) Wallr., Fl. Crypt. Germ. 3:294,295. 1831. 



Sphaeria epigaea Pers., Syn. Meth. Fung. Add. XXVII. 1801. Verrucaria 

 epigaea (Pers.) Ach. 



Superficial thallus thin, widespread, sometimes disappearing, often finely granu- 

 lose, greenish to brown or ashy; perithecia minute, 0.1-0.15 mm. across, appearing 

 as black spots in the thallus; spores oblong-ellipsoid, 16-28 X 7-10 /x. 



On soil, from New England to Virginia and westward to Iowa and Minnesota, 

 and in California. 



OTHER SPECIES REPORTED 

 Thrombium discordans (Nyl.) Zahlbr. — Southern California. 



8. Microglaena Koerb., Syst. Lich. 388,389. 1855. 



Thallus crustose, smooth to minutely warty, granulose, chinky, areolate or 

 squamulose, partly within the substratum, devoid of differentiation into layers; 

 perithecia minute to small, more or less immersed in the thalloid areoles or squam- 

 ules, the wall complete or rarely dimidiate, the superficial portion depressed to 

 convex, the ostiole minute, rarely visible; hypothecium hyaline to brown; hyme- 

 nium hyaline; paraphyses delicate, persistent; asci oblong-cylindrical; spores 2-8, 

 hyaline to brownish, ovoid-ellipsoid to ellipsoid, transversely and longitudinally 

 septate. 



The algal host is Protococcus. 



A. Thallus thin, chinky to areolate, greenish to olive gray 1. M. Hassei 



A. Thallus warty to minutely squamulose, greenish gray to whitish or ashy 



B. Spores 4 in each ascus 3. M. sychnogonoides 



B. Spores 8 in each ascus 2. M. subcorallina 



1. Microglaena Hassei Zahlbr.. Beih. Bot. Centralb. 13:152. 1902. 



Thallus thin, widespread, minutely warty, becoming chinky or areolate, greenish- 

 to olive-gray; perithecia minute, 0.2-0.3 mm. across, dimidiate, immersed, usually 

 1 in each raised areole; spores 8, hyaline or becoming brown, ovoid-ellipsoid to 

 ellipsoid, 7-9-septate transversely and 2-3-septate longitudinally, 20-30 X 9-13 /*. 



On trees, southern California. 



2. Microglaena subcorallina Hasse, Cont. U.S. Nat. Herb. 17:7. 1913. 



Thallus moderately thick, warty to minutely squamulose, whitish to dull green- 

 ish gray; perithecia minute, 0.1-0.3 mm. across, the wall complete, partly immersed, 

 1 or rarely 2 in each squamule. the superficial portion depressed to convex, dark 

 brown to black; spores 8, ellipsoid, hyaline to pale brownish, 5-8-septate trans- 

 versely and 1-3-septate longitudinally,' 34-40 X 12-18 /x. 



On trees, San Gabriel Mountains, southern California. 



3. Microglaena sychnogonoides Zahlbr., Beih. Bot. Centralb. 13:151, 152. 1902. 



Thallus thin, smooth to becoming minutely warty, composed of minute squam- 

 ules, greenish gray to ashy; perithecia minute to small, 0.15-0.4 mm. across, im- 

 mersed, usually 1 in each squamule, the wall complete, the superficial portion con- 

 vex or depressed, brownish gray to brown; spores 4, hyaline to brownish, ellipsoid, 

 7-11-septate transversely and 3-5-septate longitudinally, 20-34 X 9-11 /x. 



On trees, southern California. 



2. DERMATOCARPACEAE 



Thallus crustose to squamulose and distinctly foliose. differentiated into more 

 or less developed upper and lower cortices, algal and medullary layers, attached 

 to the substratum by rhizoids or an umbilicus; perithecia immersed, single, up- 

 right, the ostiole terminal, punctiform: paraphyses soon gelatinizing, indistinct or 

 wanting. 



The algal host is Pleurococcus. 



