30 1. VERRUCARIACEAE [ 1. Verrucaria 



F. Spores 18-22X8-9/* 7. V. silicicola 



E. Perithecia 0.3-0.6 mm. across 4. V. maura 



D. Spores rarely less than 20 ix in length 



E. Thallus smooth to sometimes chinky, olive-green to 



brownish 9. V.hydrela 



E. Thallus chinky, olive to grayish brown 10. V. margacea 



A. Thallus on rocks in dry places 



B. Spores rarely more than 15 n in length 

 C. Spores hyaline 



D. Perithecia rarely more than 0.15 mm. across 15. V. fuscella 



D. Perithecia rarely less than 0.15 mm. across 



E. Thallus grayish to ashy brown 12. V. pinguicula 



E. Thallus grayish brown to dull black .... 17. V. nigrescentoidea 



C. Spores becoming dark brown 21. V. calciseda fuscospora 



B. Spores rarely less than 15 /x in length 

 C. Thallus smooth to chinky or powdery 



D. Thallus grayish white to rose-red or pink 



E. Thallus grayish white; perithecia 0.1-0.2 mm. across . 21. V. calciseda 

 E. Thallus rose-red to pink; perithecia 0.2-0.4 mm. across 23. V. marmorea 

 D. Thallus gray to brownish- or greenish-black 



E. Thallus smooth to minutely chinky 20. V. dacryodes 



E. Thallus smooth to becoming scurfy and slightly 



granulose or powdery 22. V. rupestris 



C. Thallus more or less chinky or areolate 

 D. Spores rarely more than 20 /j. in length 



E. Thallus areolate to granulose, reddish brown ... 18. V. aquilella 

 E. Thallus chinky, areolate, ashy to greenish or sordid 



F. Thallus indistinctly chinky-areolate, sordid . . . 13. V. sordida 

 F. Thallus areolate, areoles warty, ashy to dusky green . 14. V. virens 

 D. Spores rarely less than 20 fi in length 

 E. Thallus brownish or greenish to black 



F. Spores 15-26 X 7-11 n 16. V. nigrescens 



F. Spores 21-32 X 10-15 m 19. V. viridula 



E. Thallus grayish to whitish 11. V. submuralis 



1. Verrucaria striatula Wahl, in Ach., Meth. Lich. Suppl. 21. 1803. 



Superficial thallus somewhat thickened, greenish black, marked by many 

 minute spots or lines; perithecia minute to small, 0.1-0.3 mm. across, the super- 

 ficial portion subhemispherical, with a depressed ostiole, shining black; spores 

 ellipsoid, 8-10 X 4-5 /*. 



On stones near tidewater, Maine and Massachusetts. 



2. Verrucaria ceuthocarpa Wahl., in Ach., Meth. Lich. Suppl. 22. 1803. 



Thallus thin to somewhat thick, smooth to slightly rough, areolate, greenish 

 gray to grayish black; perithecia minute to small, 0.2-0.3 mm. across, immersed, 

 the superficial portion convex, black, with a minute papillate ostiole; spores 

 ellipsoid to somewhat spherical, 6-10 X 4-8 fx. 



On rocks, Maine and Massachusetts. Zahlbruckner gives no American distri- 

 bution. 



3. Verrucaria subsuperficialis Fink; Hedrick, Mycologia 25:304. 1933. 



Thallus thin to somewhat thick, smooth or slightly rough, olivaceous, occurring 

 fully developed with perithecia in small areas, these areas interspersed in about 

 equally extensive very thin areas (hypothallus) showing the lichen hyphae and the 

 algal host cells, both the thick and thin areas remaining firm when wet; perithecia 

 minute, 0.17-0.2 mm. across, olivaceous black, spheroidal or subconical above and 

 flattened below, scattered to closely placed, entirely above the substratum and 

 readily removed with the thallus, the basal third immersed in the latter, complete 

 with perithecial wall thin below, or sometimes dimidiate and centrally open below; 

 spores ovoid-oblong, 7-9 X 4-5 ll. 



On a littoral quartz pebble. Long Island, New York. 



