378 43. BUELLIACEAE [ 172. Rinodina 



apothecia minute, 0.25-0.5 mm. across, partly immersed to adnate, the disk flat 

 to slightly convex, black, the exciple thin, colored like the thallus; hypothecium 

 yellowish to brownish; spores ellipsoid, slightly constricted at the septum, one 

 cell sometimes larger, 14-20 X 5-9 /x. 

 On rocks, California. 



13. Rinodina milvina (Wahl.) T. Fries, Nov. Act. Reg. Soc. Sci. Ups. III. 3:224. 



1861. 



Partnelia milvina Wahl., in Ach., Meth. Lich. Suppl. 34. 1803. 



Thallus moderately thick, granulose, ashy to brownish or brown, the granules 

 flat to convex, often passing into an areolate crust, or scattered upon a very thin, 

 black hypothallus; apothecia small to middle-sized, 0.4-0.8 mm. across, partly 

 immersed to adnate, commonly crowded and irregular, the disk flat, brownish 

 black, the exciple thin, colored like the thallus; hypothecium brownish to brown; 

 spores oblong to oblong-ellipsoid, 14-20 X 6-11 fx. 



On rocks, Massachusetts and Ohio. 



14. Rinodina Bischofm* (Hepp) Mass., Fram. Lich. 26. 1855. 



Psora Bischoffii Hepp, Spor. Flecht. Eur. 81,411. 1853. R. Penardiana Mull. 

 Arg. 



Thallus thin to moderately thick, minutely granulose, the granules whitish to 

 greenish gray or brownish, scattered or more commonly running together into a 

 more or less chinky, scurfy, or subareolate crust, sometimes disappearing; apothe- 

 cia minute to small, 0.3-0.8 mm. across, sessile, the disk flat to slightly convex, 

 dark brown to black, the exciple thin, colored like the thallus, rarely blackening; 

 hypothecium hyaline to yellowish; spores ovoid-ellipsoid, 15-20 X 8-12 /x. 



On rocks, from Minnesota to Texas, and westward to California. 



var. immersa Koerb., Par. Lich. 75. 1865. 

 Thallus ashy to whitish; apothecia minute, 0.2-0.5 mm. across, immersed in 

 minute pits of the substratum. 



On limestone, southern California. 



15. Rinodina atrocinerea (Dicks.) Koerb., Syst. Lich. 125. 1855. 



Lichen atrocinereus Dicks., PI. Crypt. Brit. 3:14. pi. 14, f. 9. 1793. R. sophodes 

 var. atrocinerea (Dicks.) Tuck. 



Thallus thin, composed of smooth, greenish gray to ashy, squamule-like areoles, 

 more or less scattered upon a conspicuous black hypothallus; apothecia small to 

 middle-sized, 0.5-1.2 mm. across, adnate to sessile, the disk flat to convex, dark 

 brown to black, the exciple thin, colored like the thallus, becoming crenulate, often 

 finally disappearing; hypothecium vellowish; spores ellipsoid to oblong-ellipsoid, 

 14-22 X 8-12 fx. 



On rocks and rarely on trees, Massachusetts, Ohio, Minnesota, and California. 



16. Rinodina nigra Fink, Minn. Bot. Stud. 2:695. 1901. 



Thallus thin to moderately thick, minutely areolate, the areoles somewhat con- 

 cave to flat, dark slate-colored, scattered or continuous, and forming irregular, 

 chinky areas; apothecia minute, 0.15-0.4 mm. across, partly immersed, 1-3 in 

 each areole, round to irregular, the disk slightly concave to flat, black, the exciple 

 moderately thick, colored like the thallus; hypothecium hyaline; spores oblong- 

 ellipsoid, sometimes slightly constricted at the septum, 9-15 X 5-8 /x. 



On rocks, Minnesota. 



17. Rinodina californica Magn., Meddel. Got. Bot. Tragdarg 3:16. 1927. 

 Thallus areolate, the areoles small, round to somewhat irregular, dark reddish 



brown to dark brown, or in part slightly grayish pruinose, forming a chinky crust, 

 distinctly radiately lobed at the circumference, the lobes short and flat; apothecia 

 minute to small, 0.2-0.4 mm. across, numerous, immersed, the disk flat, black,, 

 the exciple distinct, colored like the thallus; spores 8, dark greenish brown, 

 10-11 X 5-5.5 fx. 



On rocks, Santa Monica Range, California (description compiled). 



