141. Pertusaria ] 37. PERTUSARIACEAE 291 



5. Pertusaria dactylina (Ach.) Nyl., Act. Soc. Sci. Fenn. 7:447. 1863. 

 Lichen dactylinus Ach., Lich. Suec. 89. 1798. 



Thallus thin, smooth to wrinkled and uneven, ashy white, producing many 

 finger-shaped, erect, sometimes divided, cylindrical branchlets; apothecia minute 

 to small, 0.15-0.5 mm. across, borne in the tips of the branchlets, the disk concave 

 to flat, pale flesh-colored, more or less covered by a thalloid veil; spores 1, 125- 

 200 X 65-85 /*. 



On soil over mosses, New Hampshire. 



6. Pertusaria ambigens (Nyl.) Tuck., Proc. Am. Acad. 12:176. 1877. 

 Lecanora ambigens Nyl., Act. Soc. Sci. Fenn. 7:449. 1863. 



Thallus thin, smooth to wrinkled and warty, greenish gray; apothecia small 

 to middle-sized, 0.4-1 mm. across, sessile or becoming slightly elevated, the disk 

 concave to flat, flesh-colored to dark greenish, often grayish pruinose, the exciple 

 colored like the thallus, irregularly crenate, at length appearing as 2 or 3 layers; 

 spores 8, ellipsoid to ovoid-ellipsoid, 17-24 X 8-13 p.. 



On trees, Washington, Oregon, and California. 



7. Pertusaria carneopallida Nyl., Flora 51:478. 1868. 

 Lecidea carneopallida Nyl., Bot. Not. 183. 1853. 



Thallus very thin to thin, smooth to slightly rough, greenish gray to ashy, 

 sometimes disappearing; apothecia minute to small, 0.1-0.5 mm. across, immersed 

 to adnate, the disk flat to convex, pale flesh-colored, the exciple thin, colored like 

 the thallus, irregular and finally disappearing; spores 8, ellipsoid to broad-ellipsoid, 

 16-32 X 11-18 /x. 



On trees, Washington. 



8. Pertusaria tetrathalamia (Fee) Nyl., Act. Soc. Sci. Fenn. 7:448. 1863. 



Trypethelium tetrathalamia Fee, Essai Crypt. 69. 1824. P.leioplacoides Mull. 

 Arg. 



Thallus thin to moderately thick, smooth to becoming wrinkled and chinky or 

 warty, pale greenish gray to whitish; apothecia minute to small, 0.1-0.5 mm. across, 

 1 or more commonly several immersed in each convex or slightly depressed, irregu- 

 lar, wartlike elevation, the ostioles minute, papillate or scarcely prominent; spores 

 2-4 or rarely 8, ellipsoid, 65-120 X 24-36 /x. 



On trees, Florida. 



9. Pertusaria nolens Nyl., Flora 47:489. 1864. 



Thallus thin, smooth to finely chinky-areolate, lead-gray to dull ashy; apothecia 

 minute to small, 0.25-0.5 mm. across, 1 or rarely 2 immersed in an areole, the 

 ostioles black, opening to form round or more commonly irregular, flat, brownish 

 to blackening disks, the exciple rarely substellate; spores 8, ellipsoid, 28-42 X 

 14-22 p. 



On schistose rocks, Santa Monica Range, California. 



10. Pertusaria pustulata (Ach.) Duby, Bot. Gall. 2:673. 1830. 

 Porina pustulata Ach., Lich. Univ. 309. 1810. 



Thallus thin, smooth to rough and chinky or finally somewhat warty, greenish 

 gray to yellowish or brownish; apothecia minute to small, 0.15-0.4 mm. across, 

 1-4 or 5 immersed in each small, hemispherical, and irregular wartlike elevation, 

 the ostioles becoming prominent and often opening separately or converging into 

 a flat, blackish disk with a rather thick, irregular exciple; spores 2, ellipsoid, 50- 

 135 X 25-56 p. 



On trees, throughout the United States. 



11. Pertusaria lutescens (Hoffm.) Lam., Bull. Soc. Bot. 25:427. 1878. 

 Lepra lutescens Hoffm., Enum. Lich. 3. 1784. 



Thallus thin, smooth to minutely wrinkled, becoming powdery, yellow to yel- 

 lowish gray, sometimes thinly zonate toward the circumference; apothecia rare, 



