244 HERRE 



areoles, occurring generally in small, more or less determinate patches, 

 sometimes bounded by a black hypothallus. The apothecia are 

 smaller and more crowded. 



A common and variable lichen, dwelling on bark and rocks in 

 the cold and temperate regions of the northern hemisphere. 



7. BUELLIA PARASEMA (Ach.) Th. Fr. 



Lichen parasemus Ach. Lich. Suec. Prodr. 64. 1798. 

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

 Buellia parasema Th. Fr. Lich. Scand. 2: 589. 1874. 

 Buellia parasema Tuck. Syn. N. Am. Lich. II: 92. 1888. 



Thallus of small, smooth, rounded, contiguous areoles, or much 

 fissured and the areoles often sublobate; passing also into very 

 thin, almost obsolete states; or the areoles becoming thicker, rough, 

 and corrugated; color whitish gray, to dark ashy gray, the limit- 

 ing, pale or blackening hypothallus usually but little evident in 

 our specimens, or even entirely obsolete; KOH yellow; CaCl 2 2 -. 



Apothecia numerous, small to medium, closely sessile or adnate, 

 black and also brownish black; the disk at first flat, with a thin, 

 entire margin which is irregular as the disk becomes flexuous; or 

 the disk convex almost from the beginning, and soon tumid, the 

 margin disappearing; epithecium yellowish brown; paraphyses very 

 slender, coherent, thecium blue with I; hypothecium very broad, 

 brownish black; spores brown, ellipsoid, bilocular, not constricted, 



- 1 ! /*; according to Tuck. ~ ;*. 



16-29 10-24 



Common throughout on old fences, decorticated dead wood, and 

 the bark of trees; a variable species probably distributed over the 

 whole earth. 



8. BUELLIA SPURIA (Schaer.) Korb. 



Lecidea spuria Schaerer, Lich. Helvet. Spicilegium, 127. 

 Lecidea spuria Schaerer, Enum. Crit. Lich. Europ. 114. 1850. 

 Buellia spuria Korber, Parerga Lich. 183. 1865. 

 Buellia spuria Tuck. Syn. N. Am. Lich. II: 91. 1888. 



Thallus of small, flattish or plano-convex, rough-surfaced, angu- 

 lose areoles crowded together into a rimose or chinky dark ashy 

 gray crust, or else of more or less dispersed, slightly convex, 



