GEOLOGY OF LA SALLE COUNTY. 



149 



olate-diffract, areolae polyo-onal, smooth or ru- 

 o-ose, effuse, apothecia black, numerous, semi- 

 immersed. Spores 8, colorless. On detached 

 calcareous rocks. 



PYRENULA, Ach., N. & H., Tuckerm. Thallus 

 h3^pophloeoid, subcortical, rarely ektophloeoid, 

 superficial, apothecia denudate, perithecium 

 black, ellipsoid-oblonof, etc. 

 P. o-emmata, Ach., Naeof. Thallus whitish, thin, 

 apothecia black, medium to laro-e, prominent, 

 convex, perithecium black, dimidiate. Spores 

 colorless. Ach. Meth. Lich. 120. (1803.) On 

 oaks and hickories. 



P. punctiformis, Ach., Nseg. Thallus thin, effuse, 

 brown, apothecia black, shining-, minute, sessile- 

 innate, conoid, perithecium dimidiate. V. epi- 

 dermidis, Nyl. Offers a near approach to Fun- 

 gi according- to Fries, Wallroth, Tuckerman. 

 On oak and hickory. Deer Park. 



P. thelaem, Ach., Tackerm, Verrucarria, Ach. On 

 oaks and shrubs, Illinois Valley. 



P. nitida, Ach. Thallus pale yellowish or olive, 

 waxy, smooth, apothecia black, in size medium 

 to laro-e, thoug-h sometimes small, invested by 

 the thallus, g-lobose, perithecium black. Spores 

 fuscous. Sphsria, Weigfel, Obs. 45. (1772). 

 Verrucaria, Ach. L. U. 279. Nyl., etc. On 

 oaks and maples. The very pale thallus will 

 ideniif}' its location more easily. 



P. g'labrata, Ach. Thallus whitish, thin, apothe- 

 cia variable in size, black, hemispherical, conoid, 

 perithecium black. Spores fuscous. 



