32 1. VERRUCARIACEAE [ 1. Verrucaria 



less exposed, the superficial portion subhemispherical, black; spores oblong to 

 ellipsoid, 24-33 X 10-16 /i. 



On often-submerged rocks, New Hampshire, Massachusetts, and California. 



11. Verrucaria submuralis Nyl., Flora 58:14. 1875. 



V. integrella Nyl. V. rupestris var. submuralis (Nyl.) Zahlbr. 



Superficial thallus very thin, scurfy, indistinctly chinky-areolate, grayish to 

 whitish; perithecia small, 0.2-0.3 mm. across, immersed in pits in the substratum, 

 the black apex protruding beyond the thallus; spores oblong-ellipsoid to ovoid, 

 17-25 X 10-14 fi. 



On rocks, Tennessee, Illinois (?), and California. 



12. Verrucaria pinguicula Mass., Lotos 6:80. 1856. 



Thallus very thin to thin, smooth to slightly rough, becoming areolate, grayish 

 to ashy brown; perithecia minute, 0.15-0.25 mm. across, immersed 1 or more in 

 an areole, the superficial portion subhemispherical, black; spores ellipsoid, 13-16 

 X 6-8 (i. 



On limestone, New York. Zahlbruckner gives no American distribution, but 

 Tuckerman gives it in Lich. Gen. 268. 1872. 



13. Verrucaria sordida Fink, Proc. Ind. Acad. Sci. 2 73. 1918. 



Superficial thallus thin, roughened, minutely and indistinctly chinky-areolate, 

 sordid; perithecia minute to small, 0.15-0.25 mm. across, numerous, the superficial 

 portion subconical, of the same color as the thallus or darker; spores oblong- 

 ellipsoid, 16-22 X 9-12 fx. 



On calcareous rocks, Montgomery County, Indiana. 



14. Verrucaria virens Nyl., Bot. Notis. 180. 1853. 



Superficial thallus thick, sometimes thinner, chinky to areolate, the areoles wart- 

 like, ashy to dusky green; perithecia minute to small, 0.15-0.3 mm. across, at first 

 largely immersed in the thallus, later protruding, the superficial portion convex, 

 black; spores ovoid to oblong-ellipsoid, 15-21 X 7-9 fx. 



On rocks, Vermont and Massachusetts. 



15. Verrucaria fuscella (Turn.) Ach., Lich. Univ. 289. 1810. 

 Lichen juscellus Turn., Trans. Linn. Soc. Lond. 7:90. pi. 8, f. 2. 1806. 

 Superficial thallus rather thick, in small patches or becoming more widespread, 



chinky to minutely areolate, ashy gray to olive-green or blackish ; perithecia minute, 

 0.08-0.15 mm. across, usually completely immersed in the thallus, often more 

 than 1 in an areole; spores ellipsoid, 9-14 X 4-7 fx. 



On rocks, from Illinois and Wisconsin westward to California and southward 

 to Alabama. 



16. Verrucaria nigrescens Pers., Ann. Bot. Usteri 14:36. 1795. 

 V. elaeochroa Tuck. 



Superficial thallus somewhat thickened, widespread, chinky or rarely becoming 

 areolate, brownish to dull black; perithecia minute to small, 0.15-0.4 mm. across, 

 the superficial portion subhemispherical, black; spores ellipsoid, 15-26 X 7-11 fx. 



On rocks, widely distributed, northern United States and southward to 

 Louisiana. 



17. Verrucaria nigrescentoidea Fink; Hedrick, Mycologia 25:303. 1933. 

 Thallus very thin to thin, widespread, smooth to slightly rough, becoming 



areolate, grayish brown to dull black; perithecia minute to small, 0.1-0.3 mm. 

 across, dimidiate, numerous, more or less immersed, the superficial portion sub- 

 hemispherical, dull black; spores ellipsoid, 12-15 X 5-6 //,, irregularly arranged. 

 On rocks, Minnesota. 



18. Verrucaria aquilella Nyl., Flora 59:237. 1876. 



Superficial thallus thin, rather widespread, areolate to granulose, reddish brown; 

 perithecia small, 0.2-0.4 mm. across, the superficial portion subhemispherical, 

 black; spores long-oblong to ellipsoid, 12-19 X 3-5.8 /x. 



On micaceous rocks, southern California. 



