FINK—THE LICHENS OF MINNESOTA. 213 
1. Placodium elegans (Link.) Ach. Lich. Suec. 102, 255, 1798. Piate 44, A. 
Lichen elegans Link, Beitr. Naturgesch. 1: 37. 1794. 
Thallus subfoliose, suborbicular, of medium size, 25 to 70 mm. in diameter, plainly 
lobed and stellate-radious in the best developed conditions, but closely adnate, the 
lobes free and becoming long, branched, wavy, convex above, sometimes subimbricate 
and often more or less lacunose; commonly orange above but varying toward yellow- 
ish or reddish, white below or darkening; upper cortex present and of moderate 
thickness, but not always distinctly cellular, the lower cortex much thinner; 
apothecia small or middle-sized, 0.5 to 2 mm. in diameter, sessile, the disk flat 
or concave, commonly orange-colored, the exciple entire or crenulate and of the 
same color as the thallus, not disappearing in ours at least; hypothecium commonly 
pale; hymenium pale below and yellowish or brownish above; paraphyses simple or 
branched, commonly enlarged and darker toward the apex; asci variously cylindrico- 
clavate to broadly clavate; spores ovoid-ellipsoid, polar 2-celled, 9 to 18 » long and 
5 to 8.5 » wide. 
Generally distribyted over the State. On rocks. 
Throughout North America, but toward the south mostly confined to mountains. 
Known in all of the grand divisions. 
EXPLANATION OF PLATE 44.—A, Plant of Placodium elegans on rocks, showing the closely adnate and 
marginally lobed thallus and the apothecia. B, Plant of Placodium cerinum on poplar, showing the small 
apothecia. A enlarged 1} diameters; B, 2 diameters. 
2. Placodium murorum (Hoffm.) Ach. Lich. Suec. 101, 255. 1898. 
Lichen murorum Hoffm. Enum. Lich. Icon, 63. pl. 9. f. 2. 1784. 
Thallus when well developed orbicular, smaller than in the last, § to 45 mm. in 
diameter, more closely adnate than that of the last and to be regarded as crustose, 
though there is a poorly developed lower cortex over portions of the ventral surface, 
the upper cortex as in the last, the central portions commonly more or less verrucose, 
the margin passing into rather short but somewhat branched lobes, or the marginal 
lobing absent and the whole thallus composed of discrete verrucee or squamules, usu- 
ally bright yellow; apothecia small, 0.4 to 1 mm. in diameter, sessile, the disk flat or 
concave and orange red, the thalloid exciple thicker than in the last and more com- 
monly crenulate, said to inclose a thin proper exciple; hypothecium commonly pale, 
hymenium pale below, yellowish above; paraphyses simple or branched, commonly 
enlarged and yellowish or brownish toward the apex; asci clavate; spores polar 
2-celled, ovoid-ellipsoid, 10 to 15 » long and 5 to 7 « wide. 
Collected at Thief River Falls, at Rainy Lake City, and in the Misquah Hills in the 
northern portion of the State; also once as far south as Granite Falls. On rocks other 
than calcareous. 
In the northern United States and northward, and also as far south as southern 
California. Known also in South America, Europe, and Africa. 
2a. Placodium murorum miniatum (Hofim.) Nyl. Not. Sallsk. Faun. Flor. Fenn, 
5: 136. 1861. 
Lichen miniatus Hoffm. Enum. Lich, Icon. 62. 1784. 
Thallus orange or reddish, smaller, 5 to 20 mm. in diameter; ours sterile. 
Collected at Grand Portage. On rocks. 
Elsewhere in North America in California. Known also in South America and 
Europe. 
3. Placodium cinnabarrinum (Ach.) Anzi, Cat. Lich. Sondr. 43. 1860. 
Lecanora cinnabarrina Ach. Lich. Univ. 402. 1810. 
Thallus strictly crustose and closely adnate, more or less chinky or areolate, or the 
areoles scattered and forming scales, these commonly more or less crenately lobed, 
or the scales still retained in less scattered conditions and becoming somewhat imbri- 
cate; suborbicular and rather small, 5 to 30 mm. in diameter, or perhaps more often 
