119. Lecidea] 33. LECIDEACEAE 203 



mm. across, adnate, frequently clustered, the disk concave to convex, sometimes 

 irregular, black, the exciple of the same color, often raised, sometimes disappear- 

 ing; hypothecium more or less brownish; spores oblong-ellipsoid, 12-21 X 6-10 fi. 

 On sandstone, South Carolina, Wisconsin, and Minnesota. 



57. Lecidea pruinosa Ach., Meth. Lich. 55. 1803. 



L. lithophila Ach. in Fink, Cont. U.S. Nat. Herb. 14 x :77. 1910. 



Thallus widespread, smoothish, continuous, becoming rough, chinky-areolate, 

 greenish gray to ashy, sometimes disappearing, hypothallus black; apothecia small 

 to middle-sized, 0.4-1.5 mm. across, sometimes closely clustered and angular, 

 adnate or rarely sessile, the disk almost flat, blackish brown to black, rarely slightly 

 pruinose, the exciple paler, rarely disappearing; hypothecium hyaline, finally 

 brownish; spores oblong-ellipsoid, 9-15 X 5-7 fi. 



On rocks, Minnesota, Tennessee, Texas, and California. 



58. Lecidea polycarpa Floerke, in Sommerf., Suppl. Fl. Lapp. 149. 1826. 

 Thallus thin, minutely chinky-areolate, the areoles flat, greenish gray to ashy, 



sometimes disappearing, hypothallus black, sometimes absent; apothecia small to 

 middle-sized, 0.6-1.5 mm. across, adnate, usually crowded into groups and angular, 

 the disk slightly concave to flat, black, the exciple thin, black, raised; hypothecium 

 hyaline, finally brownish; spores ellipsoid, 9-13 X 4-6 yu.. 



On rocks, New Hampshire, Nebraska, South Dakota, and the Rocky Mountains. 



59. Lecidea parasema Ach., Meth. Lich. 35. 1803. 



Lichen parasemus Ach., Lich. Suec. 64. 1798. L. enteroleuca Ach. 



Thallus very thin to thin, smoothish to somewhat rough, becoming chinky to 

 areolate, and sometimes minutely granulose, greenish gray to ashy; apothecia mi- 

 nute to middle-sized, 0.3-1 mm. across, adnate, scattered, the disk flat to more or 

 less convex, black, the exciple thin, black, becoming flexuous and soon disappear- 

 ing; hypothecium hyaline to brown; spores ovoid-ellipsoid, 8-17 X 5-9 /a. 



On rocks and trees, throughout the United States. 



The relationship between L. parasema and L. enteroleuca (Ach.) T. Fries is 

 not clear, and it has seemed best to place our material under L. parasema and 

 varieties thereof. 



var. ambigua (Mass.) Boist., Nouv. Fl. Lich. 221. 1903. 

 Biatora ambigua Mass., Ric. Lich. 124. 1852. L. enteroleuca var. ambigua 



(Mass.) Tuck. 

 Thallus thin, smooth to slightly rough, ashy; apothecia yellowish to blackish 

 and obscurely grayish pruinose. 



On old wood, Minnesota, Oregon, and Washington. 



var. flavens Nyl., Not. Sallsk. Faun. Flor. Fenn. 5:217. 1861. 

 L. enteroleuca var. flavida E. Fries. 



Thallus yellowish, smooth to chinky, surrounded and dissected by a black hypo- 

 thallus; the disk somewhat grayish pruinose, the exciple thin, commonly persistent. 

 On trees, New England and Minnesota, and perhaps generally distributed. 



var. muscorum (Wulf.) Fink n. comb. 

 Lichen muscorum Wulf., in Jacq., Coll. Bot. 4:232. 1790. L. enteroleuca var. 



muscorum (Wulf.) T. Fries. L. enteroleuca var. Wulfenii Koerb. 

 Thallus warty, white to ashy; apothecia very black, confluent, the disk flat to 

 convex, the exciple pale yellow to darker and finally brown. 

 On soil and mosses, New Hampshire, 

 var. achrista (Sommerf.) Mong., Bull. Acad. Geogr. Bot. 9:201. 1900. 

 L. elaeochroma var. achrista Sommerf., Suppl. Fl. Lapp. 150. 1826. L. entero- 

 leuca var. achrista (Sommerf.) Tuck. 

 Thallus thin and smooth to chinky, warty, dark ashy to whitish; apothecia 

 flat to tardily convex, becoming flexuous; hypothecium pale yellow to darker and 

 brownish. 



On trees, throughout the United States. 



