FINK—THE LICHENS OF MINNESOTA. 
Section II, Thallus not lobed (except in nos. 5 and 16), 
Spores often more than 20 # in length. 
Spores reaching 50 in length. 
Thallus thick and rough... ...........0.....-...------- 15. 
Thallus thinner. 
Thallus smoothish; apothecia large, flesh-colored or 
white-pruinose. ........2....--.5.---22-5--2-2--- 14. 
Thallus verrucose, chinky or subareolate; apothecia 
small or minute, black....................-.----- 
Spores not reaching 50 »: in length. 
Apothecia immersed, or becoming adnate. 
Apothecia always becoming adnate, disk black, exciple 
entire... 0.0.2.2 eee Isb 
Apothecia sometimes becoming adnate. 
Disk light brown or darker, commonly white-prui- 
nose. . 2.2.2.2 22 ee ee eee eee 19. 
Disk of same color as above, not pruinose, but fre- 
quently punctiform.......................-.--- 19a 
Apothecia always immersed. 
Thallus ashy to brownish. 
Thallus thick and becoming areolate; disk black, 
medium-sized... ......-.-0-0-5-50002- 20000 eee eee 18. 
Thallus thinner, never becoming areolate; disk 
usually minute or irregular.............2.2..--- 18a 
Thallus finally darker-colored, 
Thallus ashy to olivaceous; disk reddish or brownish; 
plant found on rocks frequently wet.........-..- 20. 
Thallus blackish-olivaceous. ..............-.---..-- I8e. 
Spores never surpassing 20 ” in length. 
Apothecia always sessile, or varying in position from sessile 
to adnate. 
Apothecia always sessile; disk dark; exciple entire or 
subcrenulate; margin of the thallus usually lobed.... 5. 
Apothecia either sessile or adnate. 
Disk whitish buff or more or less whitish-pruinose. 
Exciple entire and usually regular............-..-- 3. 
Exciple angulate and variously irregular........... 3a 
Disk light brown to black. 
Thallus quite thick and more or less imbricate-lobed. 16. 
Thallus not lobed. 
Thallus thick and rough, areolate or verrucose. 
Exciple persistent. 
Exciple often flexuous, entire, or crenate...... 
Exciple scarcely ever flexuous, entire, or cre- 
173 
LL. tartarea. 
LL. pallescens. 
. L. mutabilis. 
. L. cinerea gib- 
hosa. 
L. calcarea. 
a. L. calearea con- 
torta. 
L. cinerea, 
. L. cinerea lae- 
vata. 
LL. lacustris. 
LL. cinerea micro- 
spora. 
L. frustulosa. 
L. patlida. 
. L, pallida angu- 
losa. 
L. melanaspis. 
7a. L. subfusca allo- 
phana, 
. DL. subfusea. 
. L. subfuscacam- 
pestris. 
