50 4. PYRENULACEAE [ 16. Leptorhaphis 



21. Arthopyrenia hyalospora (Nyl.) Fink n. comb. 



Verrucaria hyalospora Nyl, Mem. Soc. Imp. Sci. Nat. Cherb. 5:337. 1857. 

 Pyrenula hyalospora (Nyl.) Tuck. 



Superficial thallus widespread, very thin and disappearing, ashy white; peri- 

 thecia rather large, 0.4-0.8 mm. across, superficial portion hemispherical with 

 papillate ostiole, black, the wall dimidiate; spores 3- and rarely 4-5-septate, ellip- 

 soid, 20-25 X 9-11 /a, irregularly arranged. 



On trees, New England to Florida and westward to Iowa. 



22. Arthopyrenia quinqueseptata (Nyl.) Mull. Arg., Flora 68:326. 1885. 

 Verrucaria quinqueseptata Nyl., Mem. Soc. Acad. Maine et Loire 4:58. 1858. 



Pyrenula quinqueseptata (Nyl.) Tuck. 



Thallus widespread, thin, sometimes disappearing, ashy white; perithecia rather 

 large, 0.4-0.8 mm. across, the wall dimidiate, superficial portion hemispherical, 

 black, the ostiole minute, sometimes visible; spores 5-7-septate, linear-oblong, 

 16-27 X 5-8 ix, irregularly arranged. 



On trees, from Pennsylvania to Florida and westward to Iowa and Minnesota. 



OTHER SPECIES REPORTED 



Arthopyrenia analeptella (Nyl.) Arn. — California. 



Arthopyrenia macrocarpa (Koerb.) Zahlbr. — Massachusetts and Louisiana. 



Arthopyrenia sphaeroides (Walk.) Zahlbr. — California. 



16. Leptorhaphis Koerb., Syst. Lich. 371. 1855. 



Thallus forming a thin, smooth to rough crust over the substratum, partly or 

 wholly within the substratum, devoid of differentiation into layers; perithecia 

 minute to small, more or less immersed, the superficial portion subhemispherical, 

 the ostiole minute, the wall dimidiate or complete; hypothecium hyaline to dark 

 brown; hymenium hyaline; paraphyses branched and interwoven or rarely un- 

 branched; asci clavate to cylindrico-clavate; spores 4-8, hyaline, acicular, straight 

 or curved, 3-7-septate, the cells cylindrical. 



The algal host is Trentepohlia. 



1. Leptorhaphis epidermidis (Ach.) T. Fries, Nov. Act. Soc. Sci. Ups. III. 

 3:373. 1861. 

 Lichen epidermidis Ach., Lich. Suec. 16. 1798. Sagedia oxyspora (Nyl.) Tuck. 



L. oxyspora (Nyl.) Koerb. 

 Thallus very thin, slightly scurfy, ashy, often disappearing, or imbedded in the 

 substratum and invisible; perithecia minute, 0.08-0.2 mm. across, partly immersed 

 in the substratum, the superficial portion subhemispherical, black, the ostiole 

 minute, the perithecial wall brownish black and dimidiate; paraphyses slender, 

 distinct, commonly unbranched; asci long-clavate ; spores 8, acicular, more or less 

 curved, 3-7-septate, 20-34 X 2-4 /x. 



On trees, from New England to Florida and westward to Illinois and Minne- 

 sota. 



17. Polyblastiopsis Zahlbr., in E. & P., Nat. Pfl. l':65. 1907. 



Thallus forming a thin, smooth crust over the substratum, partly or wholly 

 within the substratum, devoid of differentiation into layers; perithecia minute to 

 small, more or less immersed, the superficial portion commonly hemispherical or 

 convex, the ostiole minute, the wall dimidiate or complete; hypothecium hyaline 

 to brown; hymenium hyaline or brownish above; paraphyses branched and netlike 

 interwoven; asci clavate to cylindrico-clavate; spores 1-8, hyaline, ovoid-ellipsoid 

 to oblong-ellipsoid, transversely and longitudinally septate, the cells cubical. 

 The algal host is Trentepohlia. 



A. Spores less than 50 n in length 

 B. Spores less than 25 n in length 



C. Spores 3-5-septate transversely 7 - P. fallax 



C. Spores 5-7-septate transversely 6. P. fallaciosa 



