FINK—THE LICHENS OF MINNESOTA. 993 
3d. Rinodina sophodes exigua (Ach.) Tuck. Syn. N. A. Lich. 1: 208. 1882. 
Lichen exiguus Ach, Lich. Suec. 69. 1798. 
Thallus small, sometimes becoming scurfy or disappearing; apothecia minute or 
smaller than usual, the disk becoming convex, the thalloid exciple becoming crenu- 
late and disappearing; spores rather small, frequently more than 8 in each ascus, 
in ours sometimes reaching 30. 
Generally distributed over the State. On trees and old wood. 
Found in all portions of North America. Known also in all of the grand divisions 
except Asia. 
4. Rinodina bischoffii Koerb. Par. Lich. 75. 1865. 
Thallus composed of small granules, these running together to form a usually 
thin, more or less chinky, scurfy, or rarely subareolate crust, this either scattered 
or continuous and spread irregularly over rather small areas of the substratum, in 
some of ours becoming thicker and in others tending to disappear; from whitish 
to sea-green or brownish; apothecia small or subminute, 0.4 to 0.8 mm. in diameter, 
sessile, the disk dark brown and becoming blackish, flat or somewhat convex, the 
thalloid exciple entire and persistent, but rarely blackening, a thin proper exciple 
within the thalloid one; hypothecium commonly pale; hymenium pale below and 
brownish above; paraphyses somewhat coherent, simple or rarely branched toward 
the commonly enlarged and brownish apex; asci clavate or ventricose-clavate; spores 
ovoid-ellipsoid, 15 to 20 » long and 8 to 13 » wide, the wide interval between the 
two cells indicated usually by a dark band. 
Doctor Koerber recognized two subspecies, protuberans and immersa, the former 
with distinct thallus and elevated-sessile apothecia, the other with both thallus and 
apothecia more or less immersed in the substratum. Ours corresponds to the former. 
Collected at Mankato, at Morton, and in the Leaf Hills. On calcareous rocks and 
pebbles. No doubt occurring on such substrata elsewhere in the State. 
Elsewhere in North America in Illinois, Iowa, Kansas, Texas, and the Rocky 
Mountains. Known also in Europe and Africa. 
5. Rinodina lecanorina Mass. Sched. Crit. Lich. Exsicc, 48. 1855. 
Mischoblastia lecanorina Mass. Ric. Lich. 41. f. 70. 1852. 
Thallus composed of flat or somewhat convex areoles, these small to middle, 
sized, 0.3 to 1.5 mm. across, and usually widely spread over the substratum as a con- 
tinuous or more or less broken crust; sea-green varying toward olivaceous; apothecia 
small or minute, 0.3 to 0.8 mm. in diameter, immersed one or more in each areole, or 
in ours becoming more or less superficial upon the rather poorly developed thallus 
and showing a thalloid exciple, which finally disappears, the disk flat or convex, 
dark brown or black in color, usually rounded but sometimes more or less irregular; 
hypothecium pale; hymenium pale below and brownish above; paraphyses simple 
or branched; asci clayate; spores oblong or oblong-ellipsoid, 15 to 21 » long and 9 to 
10 » wide. 
Reported from Mankato, Oak Island, Koochiching, and Rainy Lake City. On 
granitic rocks. Our plants differ from European material in the poorer thallus devel- 
opment and more superficial apothecia. Doctor Zahlbruckner has named, but as 
yet not described, Rinodina ioensis, from Fayette, lowa, which some of our material 
externally quite as much resembles as it does R. lecanorina. 
Not known elsewhere in North America, Found in Europe. 
6. Rinodina nigra Fink, Minn. Bot. Stud. 2: 695. 1901. 
Thallus of moderate thickness, composed of flat or somewhat concave areoles, each 
areole 0.5 to | mm. in diameter, without cortex, dark slate-color, commonly irregular 
and spread as a continuous or more or less broken layer over larger or smaller areas 
