FINK—THE LICHENS OF MINNESOTA. L151 
KEY TO THE SPECIES. 
On wood. 
Thallus plainly foliose, not sorediate or isidioid. .........- 1. P. rubiginosa. 
Thallus plainly foliose, sorediate or isidioid......--...-..-. la. P. rubiginosa 
cono plea. 
Not confined to wood. 
On rocks or wood. 
Squamulose instead of plainly foliose; spores 16 to 22 
plong.......-2----- 22-22 eee ee ees 2. P. leucosticta. 
Squamulose instead of plainly foliose; spores 20 to 28 
pelong. .. 2.22. eee eee eee eee eee eee eee ee eee 4. P. lepidiota. 
On rocks always. 
On calcareous rocks or pebbles. 
Blue black hypothallus prominent. .... wee eeeee 6. P. nigra, 
Blue black hypothallus absent... ........-.----- 5. P. petersir. 
On rocks other than calcareous; thallus of small squam- 
Ules. 0c ee eee ee eee neee 3. P. microphylla. 
1. Pannaria rubiginosa (Thunb.) Del. in Bory, Dict. Class. Hist. Nat. 13: 20. 1828- 
1831. 
Lichen rubiginosus Thunb. Prodr, Fl. Cap. 176. 1794. 
Thallus plainly foliose, usually orbicular, middle-sized or larger, 20 to 65 mm. in 
diameter, closely attached to the substratum, rather smooth above, plainly lobed, the 
lobes quite long and sinuate or divided toward the more or less raised and crenate ends, 
usually more or less imbricated, sea-green or varying toward ashy, yellowish or lead- 
color, below lighter in color and clothed with conspicuous rhizoids of the same color, 
though the whole lower surface, especially toward the margin, is obscured and dark- 
ened by the more or less conspicuous blue black hypothallus; lower cortex absent in 
some spots and very poorly developed at best; apothecia small, 0.5 to 2.5 mm. in 
diameter, sessile, the disk brown, the thalloid margin crenulate; hypothecium more 
or less brownish; hymenium colorless below and brownish above; asci clavate; para- 
physes simple or rarely branched, the apex commonly enlarged and brownish; spores 
simple, colorless, ellipsoid-pointed, 14 to 24 » long and 6 to 10 » wide. 
Thus far reported only along the international boundary, from Kettle Falls west- 
ward. However, the relation of the present plant, and the subspecies below, to 
Pannaria lepidiota is a close one. On cedars in swamps. 
The plant is widely distributed in North America. It is also known in all the 
grand divisions. 
la. Pannaria rubiginosa conoplea (Ach.) Nyl. Syn. Lich. 2: 30. 1860. 
Parmelia conoplea Ach. Lich. Univ. 467. 1810. 
Thallus grayish-sorediate or isidioid, passing toward the center into a continuous 
crust; apothecia with algal cells of thalloid exciple wanting, or even strictly biatoroid. 
Along the western part of the international boundary from Beaudette to Harding. 
Also collected at Tower. On cedars in swamps. 
Known in North America from New England northward into British America and 
also in California. Also known in South America and Europe. 
2. Pannaria leucosticta Tuck. Proc. Amer. Acad. 4: 404. 1860. PLATE 25, 
Thallus squamulose and scarcely approaching a foliose condition, the squamules 
resting upon a thin, blackish hypothallus, closely adnate or the margins raised, those 
of the circumference more expanded and elongated, crenate or pinnately lobed, 
those of the center smaller, more imbricated and ascendant with entire or dentate- 
crenate margins, these more frequently white-powdery; squamules 0.5 to 1 mm. wide 
