FINK—-THE LICHENS OF MINNESOTA. 183 
16. Lecanora melanaspis Ach. Lich. Univ. 427. 1810. 
Parmelia melanaspis Ach. Meth. Lich. 196. 1803. 
Thallus thick, crustose, and becoming verrucose-rugose or subareolate or, especially 
toward the margin, subfoliose, and showing linear, branched, and more or less imbri- 
cated lobes, ashy to whitish or brownish, covering considerable areas and showing a 
suborbicular tendency (plants at hand being 25 to 50 mm. in diameter), well devel- 
oped and showing a cortical layer; apothecia small to middle-sized, 1 to 2 mm. in 
diameter, adnate or closely sessile, the disk flat or more or less convex, dark brown 
to blackish and rarely pruinose, the exciple commonly entire, but rarely becoming 
somewhat irregular or tending to disappear; hypothecium pale; hymenium pale 
beneath, usually brownish above; paraphyses simple or rarely branched, frequently 
enlarged, and somewhat darkened toward the apex; asci clavate; spores short-ellip- 
soid, 8 to 14 » long and 5 to 9 » wide. 
The plant seems near Lecanora rubina in respect to thallus structure and should 
perhaps be placed nearer that species. 
Collected at Granite Falls. On rocks. 
Elsewhere in North America in Greenland, Nebraska, Kansas, South Dakota, and 
California. Known also in Europe. 
Lecanora sp. of the fifth report of the preliminary survey. 
17. Lecanora mutabilis (Ach.) Nyl. Mém. Soc. Sci. Nat. Cherb. 2: 324. 1854. 
Ureeolaria mutabilis Ach. Lich. Univ. 335, 1810. ° 
Thallus crustose and of moderate thickness, verrucose, chinky or subareolate, 
dark-ashy or varying toward yellowish, usually suborbicular and middle-sized, 25 to 
80 mm. in diameter; apothecia small or minute, 0.5 to 1 mm, in diameter, immersed 
or becoming superficial, the disk concave and urceolate, commonly black, surrounded 
by a proper exciple and this in turn by an inflexed thalloid one; hypothecium pale; 
hymenium pale throughout or darkened above; asci cylindrico-clavate to short- 
clavate; paraphyses slender and variously curved, simple or branched; spores round- 
ish-ellipsoid, 30 to 52 » long and 16 to 35 » wide. 
The plant is generally distributed over the northern portion of the State, but has 
been confused with Pertusaria leioplaca. On trees. 
Elsewhere in North America in Massachusetts and New York. Known also in 
Europe and Africa. 
Lecanora verrucosa mutabilis of the preliminary reports. 
18. Lecanora cinerea (I..) Sommerf. Suppl. Fl. Lapp. 99. 1826. 
Lichen cinereus 1.. Mant. Pl. 1: 132. 1767. 
Thallus crustose, of moderate thickness and more or less roughened; commonly 
plainly areolate but sometimes smoother and chinky, or rarely verrucose rather than 
areolate, the areoles or verrucee commonly about 1 mm. in diameter, ashy (cinereous) 
varying toward whitish or brownish, sometimes orbicular, 30 to 85 mm. in diameter, 
or becoming irregular and more widely spread over the substratum, in the orbicular 
conditions the margin sometimes delicately zonate; apothecia small to almost middle- 
sized, or sometimes minute, 0.5 to 1 mm. in diameter (or 1.5 according to Nylander), 
immersed, the disk commonly flat and black, the exciple entire and sometimes 
blackening; hypothecium pale; hymenium pale below and frequently brownish or 
olivaceous above; paraphyses simple or rather rarely branched, the apices sometimes 
slightly enlarged and colored; asci clavate; spores ovoid or ellipsoid, 14 to 26 » long 
and 7 to 16 » wide. 
The plant is very variable, and it might perhaps conduce to clearness to follow the 
European lichenists in recognizing even a larger number of subspecies. 
Generally distributed over the State. On rocks other than calcareous. 
Known throughout North America, Found in all of the grand divisjons except 
Australia, 
