246 HERRE 



10. BUELLIA STELLULATA (Tayl.) Mudd. 



Lecidea stellulata Taylor, in Mackay, Fl. Hibern. II: 118. 1836. 

 Buellia stellulata Mudd, Man. Brit. Lich. 216. 1861. 

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



Thallus from small and more or less orbiculate becoming effuse 

 and spreading extensively, but bounded by a thin black hypothallus; 

 thin, of minute to very minute, flat or plano-convex areoles, finely 

 rimose; color white, ashy gray, and dusky ashen; KOH yellow; 

 CaCl 2 2 -. 



Apothecia numerous, minute to very minute, innate-sessile be- 

 tween the areoles, becoming crowded and confluent, black; the disk 

 plane with a thin erect black or occasionally gray margin which 

 finally disappears; epithecium and hypothecium blackish brown 

 or umber; paraphyses simple, thread-like, sub-coherent, their tips 

 enlarged, blunt, rounded; thecium blue with I; spores bilocular, 



6-8 

 blunt-ellipsoid, /*. 



Common on various rocks in the maritime area and in the foot- 

 hills. A cosmopolitan lichen. 



The minute white areoles thickly studded with the black apothecia 

 often give it a "pepper and salt" or "Milky Way" appearance. 



ii. BUELLIA RETROVERTENS Tuck. 



Buellia retrovertens Tuck. Syn. N. Am. Lich. II: 89. i< 



Thallus of small or minute, separate or contiguous, smooth, plano- 

 convex, rounded, angulose, or sub-lobate whitish-gray squamules on 

 a more or less evident black hypothallus; KOH yellow; CaCW^ . 

 Apothecia adnate, minute to small, disk at first flat, dull black, 

 with an entire, slightly elevated, brown-black margin; becoming 

 convex when the margin is obsolete; epithecium a narrow brown- 

 black line; hypothecium dark brownish black; paraphyses coherent, 

 with abrupt globular pale violaceous heads; thecium pallid, blue 

 with I; asci spatulate, nearly as high as thecium; spores long-ellip- 

 soid, dark brown, little or not at all constricted at the middle, ap- 



5-8 

 parently with a narrow and little evident halo, /'. 



