54 4. PYRENULACEAE [ 19. Porina 



dimidiate; spores fusiform, larger toward one end, 3-septate, 16-20X3.5-6//., 

 biseriately to irregularly arranged. 



On trees, Florida, Texas, and Illinois. 



4. Porina Carpinea (Pers.) Zahlbr., in E. & P., Nat. Pn. 1:60. 1907. 



Verrucaria Carpinea Pers., in Ach., Meth. Lich. 120. 1803. 



Thallus thin, smooth to slightly wrinkled, greenish gray to ashy or brownish; 

 perithecia minute to small, 0.15-0.3 mm. across, the superficial portion hemi- 

 spherical, black, shining, the ostiole minute, indicated by a whitish coloration 

 and often becoming visible, the wall dimidiate; spores fusiform, 3-septate, 18-24 

 X 5-7.5 //., uniseriately to irregularly arranged. 



On trees, California. 



5. Porina viridiseda (Nyl.) Zahlbr., Cat. Lich. Univ. 1:409. 1922. 



Verrucaria viridiseda Nyl., Mem. Soc. Acad. Maine et Loire 4:55. 1858. 

 P. viridiseda f. albiseda (Nyl.) Zahlbr. 



Thallus thin, smooth, greenish gray to ashy or whitish; perithecia minute, 

 0.1-0.25 mm. across, the superficial portion hemispherical to subconical, black, 

 the ostiole minute, rarely visible, the wall dimidiate; spores ovoid to ovoid- 

 ellipsoid, 1-septate, 9-10 X 3-4 //,, uniseriately to irregularly arranged. 



On trees, Florida. 



6. Porina salicina Mull. Arg., Hedwigia 34:34. 1895. 



Thallus thin, ashy white, smooth to slightly rough; perithecia minute to small, 

 0.15-0.35 mm. across, the superficial portion hemispherical, dull black or whitish 

 pruinose, the ostiole minute and rarely visible, the wall dimidiate; spores ovoid- 

 ellipsoid, 1-septate and constricted at the septum or rarely 3-septate, 13-16 X 

 4.5-5 /a, uniseriately arranged. 



On trees, Louisiana. 



7. Porina chlorotica (Ach.) Mull. Arg., Rev. Mycol. 6:20. 1884. 



Verrucaria chlorotica Ach., Lich. Univ. 283. 1810. Sagedia chlorotica (Ach.) 

 Mass. 



Thallus thin, smooth, gelatinous, becoming scurfy, widespread, olive-green to 

 ashy gray; perithecia minute to small, 0.1-0.4 mm. across, partly immersed in a 

 thalloid veil, the superficial portion convex, black, the ostiole minute, rarely visible, 

 the wall dimidiate; spores 3-septate, fusiform-dactyloid, 15-23 X 3.5-4.5 /a, ir- 

 regularly arranged. 



On rocks and trees, Massachusetts and North Carolina. 



Tuckerman described a form having spores 5-7-septate and 25-40X4.5-7//.. 



8. Porina lectissima (E. Fries) Zahlbr., in E. & P., Nat. Pfl. 1:66. 1907. 

 Segestria lectissima E. Fries, Syst. Orb. Veg. 287. 1825. 



Thallus thin, smooth, becoming granulose, pale olive-green to reddish yellow; 

 perithecia minute to small, 0.15-0.3 mm. across, the superficial portion convex, 

 reddish to dull black, the ostiole becoming large, the wall dimidiate; spores fusi- 

 form, 3-septate, 18-30X4.5-7//,, irregularly arranged. 



On rocks, New Hampshire. 



9. Porina olivacea (Pers.) A. L. Smith var. microspora Fink; Hedrick, My- 



cologia 25:308. 1933. 



Thallus superficial, thin, smooth or somewhat wrinkled or chinky, dark olive- 

 brown; perithecia minute, 0.15-0.25 mm. across, hemispherical, the wall dimidiate, 

 the ostiole invisible, slightly immersed, the superficial portion black; hypothecium 

 and hymenium hyaline; spores long-ellipsoid, 3-septate, 15-22 X 4-4.5 ju, arranged 

 irregularly. 



On trees, New Hampshire. (The typical form of the species is European.) 



