118. Peltigera] 33. LECIDEACEAE 189 



11. Peltigera spuria (Ach.) DC, in Lam. & DC, El Franc. III. 2:406. 1815. 

 Lichen spurius Ach., Lich. Suec. 159. 1798. P. canina var. spuria (Ach.) Schaer. 

 Thallus small to rarely middle-sized, ascending to suberect, greenish gray to 



ashy and brownish, partly covered with trichomatic hyphae, the lobes small with 

 round to crenate margins ; whitish to cream-colored below, reticulated with whitish 

 veins bearing few rhizoids; apothecia small to middle-sized, 2-5 mm. across, borne 

 on short, somewhat digitately clustered lobules, rolled backward, the disk reddish 

 brown, the exciple crenulate or finely toothed; hypothecium brownish; spores 

 hyaline, 3-7-septate, acicular, 45-75 X 3.5-4.5 (i. 

 On soil, throughout the United States. 



12. Peltigera sorediata (Schaer.) Fink; Corring., Ohio State Univ. Bull. 25: 



no. 6. 356,357. 1921. 



P. canina var. spuria f. sorediata Schaer., Enum. Lich. Eur. 21. 1850. P. canina 

 var. sorediata (Schaer.) Fink. P. leptoderma Nyl. 



Thallus small, adnate, greenish gray to deep gray or ashy, thickly covered 

 with trichomatic hyphae and round areas of grayish soredia, the scattered lobes 

 irregular, round to crenate, and slightly ascending toward the margins; ashy white 

 to cream-colored below, reticulated with whitish veins, bearing whitish rhizoids; 

 apothecia small, 1.5-3.5 mm. across, rare, borne on narrow, extended, digitately 

 clustered lobules, round to horizontal to partly rolled backward, the disk dark 

 brown, the exciple becoming crenulate; hypothecium brownish; spores hyaline, 

 5-7-septate, acicular, 50-66 X 3-3.5 ju,. 



On soil and over mossy rocks, throughout the United States, preferring moun- 

 tains southward. 



13. Peltigera pulverulenta (Tayl.) Nyl., Syn. Lich. 1:325. 1860. 

 Peltidea pulverulenta Tayl.; Hook., Lond. Journ. Bot. 6:184. 1847. 



Thallus middle-sized to large, closely adnate, smooth to chinky and granulose 

 to powdery, sometimes more or less pitted, greenish gray to ashy and lurid brown, 

 with broad, slightly imbricated, round to irregular lobes, often slightly ascending 

 toward the margins; whitish to brownish below, reticulated with brownish, con- 

 fluent veins; apothecia middle-sized, 4-6 mm. across, borne on short, digitately 

 clustered lobules, round, often horizontal, the disk dark brown, the exciple often 

 obscurely irregular or crenulate; hypothecium hyaline to brownish; spores hyaline, 

 3-7-septate, acicular, 60-100 X 3-4 fi. 



On soil, New Hampshire, sterile and uncertainly included. 



OTHER SPECIES REPORTED 

 Peltigera Evansiana Gyelnik — New Hampshire, Vermont, Connecticut, and Mich- 

 igan. 



33. LECIDEACEAE 



Thallus crustose, granulose to squamulose, entire to lobed at the margin, dif- 

 ferentiated into cortical, algal, and medullary layers or showing little differentia- 

 tion, attached to the substratum by hyphal rhizoids; apothecia round, immersed 

 to sessile or rarely pedicellate, the proper exciple well developed. 



The algal hosts are Gloeocapsa, Pleurococcus, and Protococcus. 



A. Spores non-septate 



B. Parasitic on other lichens 121. Nesolechia 



B. Not parasitic on .other lichens 



C. Spores very large, thick-walled 122. Mycoblastus 



C. Spores not large, thin-walled 



D. Thallus crustose 119. Lecidea 



D. Thallus squamulose 120. Psora 



A. Spores septate 



B. Spores transversely 1-many -septate 

 C. Spores 1 -septate 



D. Spores large, thick-walled 124. Megalospora 



D. Spores small, thin-walled 123. Catillaria 



