15. Arthopyrenia ] 4. PYRENULACEAE 49 



15. Arthopyrenia conformis (Nyl.) Herre, Proc. Wash. Acad. Sci. 12:52. 1910. 

 Verrucaria conformis Nyl., Flora 47:357. 1864. 



Thallus thin, smooth, finally chinky, ashy; perithecia numerous, minute to 

 small, 0.1-0.4 mm. across, semi-immersed, the superficial portion hemispherical, 

 black, dimidiate, the ostiole minute, very rarely visible; asci cylindrical, hyaline 

 internally; spores narrowly ellipsoid, 1 -septate, constricted strongly at the septum 

 and at the middle of each cell, giving the appearance of being 3-septate, or finally 

 3-septate, 9-16X3.5-5.5^., commonly uniseriately arranged. 



On trees, Santa Cruz Peninsula, California. 



16. Arthopyrenia distans (Willey) Zahlbr., Cat. Lich. Univ. 1:276. 1921. 

 Verrucaria distans Willey, Enum. Lich. New Bedford, Mass. 38. 1892. The- 



lidiurn distans (Willey) Zahlbr. 



Thallus very thin to thin, smooth to rough, grayish to ashy, sometimes dis- 

 appearing; perithecia minute, 0.1-0.25 mm. across, partly immersed, the wall 

 dimidiate, the superficial portion subhemispherical, black; spores 8, hyaline, 

 ellipsoid, 1-2 or rarely 3-septate, 14-21 X 5-7 ft, irregularly arranged. 



On shaded rocks, near New Bedford, Massachusetts. 



17. Arthopyrenia dimidiata Fink; Hedrick, Mycologia 25:306. 1933. 

 Thallus very thin to thin, smooth to somewhat rough, continuous to chinky 



and sometimes areolate, grayish to ashy; perithecia minute, 0.1-0.25 mm. across, 

 the superficial portion subhemispherical, dull black, the wall dimidiate; spores 

 reaching 8, ellipsoid, 1- rarely 2-septate, the upper cell larger, 10-14X5-6/;., 

 irregularly arranged. 



On rocks, Connecticut. 



18. Arthopyrenia punctiformis (Schrank) Mass., Ric. Lich. 16S. f. 335. 1S52. 

 Lichen punctiformis Schrank, Bayer. Flora 2:513. 1789. Pyrenula punctiformis 



(Schrank) Trevis. Pyrenula sub punctiformis Nyl. A.floridana Zahlbr. Ver- 

 rucaria punctiformis (Schrank) Pers. 



Thallus rudimentary, the imbedded portion indicated by a lighter coloration 

 of the substratum, more or less pronounced, frequently disappearing; perithecia 

 minute to small, 0.1-0.5 mm. across, the latter the long dimension in oblong 

 forms, round to oblong, the wall dimidiate, superficial portion depressed, convex, 

 black, the ostiole punctiform, usually indicated by a whitish area; spores 1-3- 

 septate, oblong-ellipsoid, 18-24 X 5-9 fi, uniseriately to irregularly arranged. 



On trees, throughout the eastern states and westward to Missouri and Minne- 

 sota, reappearing in California. 



19. Arthopyrenia Cinchonae (Ach.) Mull. Arg., Flora 66:287. 1883. 

 Verrucaria Cinchonae Ach., Syn. Meth. Lich. 90. 1814. Pyrenula Cinchonae 



(Ach.) Tuck. Verrucaria prosta?is Mont. 



Thallus whitish, superficial portion very thin and disappearing; perithecia 

 small to middle-sized, 0.2-0.5 mm. across, superficial portion convex, black, the 

 ostiole minute, indicated by a whitish area, the wall dimidiate; spores 1-3-septate, 

 oblong-ellipsoid, 17-25X6-9 fi, for most part obliquely uniseriate. 



On trees, South Carolina, Florida, Alabama, Louisiana, and Texas. Nylander 

 describes under same name a plant having spores 25-30 X 7-8 /x. 



20. Arthopyrenia Cerasi (Schrad.) Mass., Ric. Lich. 167. f. 332. 1852. 

 Verrucaria Cerasi Schrad., Crypt. Exsicc. No. 174. 1797. 



Superficial thallus rudimentary or absent, imbedded thallus indicated by a 

 sometimes widespread, thin, shining, ashy gray or lead-colored to brownish area; 

 perithecia small to middle-sized, 0.3-0.8 mm. across, elliptical, the superficial 

 portion slightly convex, black, shining, the perithecial wall dimidiate; spores 3- 

 septate, ellipsoid, rounded at the ends, 15-25 X 4-8 /x. 



On young oaks, Maryland, Iowa, and California. 



