38 HERRE 



PYRENOCARPE^:. 



Thallus crustaceous, squamulose, rarely foliaceous, more rarely 

 fruticose. Gonidia of Pleurococcus, Chroolepus or Trentepohlia, 

 Phyllactidium, Nostoc, or Sirisiphon algae. Soredia are absent or 

 very rare. Apothecia globular or hemispherical, opening only by a 

 pore at the summit, immersed in the thallus with only the apex 

 protruding, or sessile; naked or more or less covered by a thalline layer; 

 solitary, or confluent and forming a stroma; a proper exciple or margin, 

 known as the perithecium, pale to black, closed or open below (dimi- 

 diate) ; within this a more or less distinct envelope, the amphithecium, 

 enclosing a globose hymenium, the nucleus of many authors, which is 

 soft, gelatinous, and often contains algae or oil drops. Paraphyses 

 simple, or branched and then twining and net-like; commonly soon 

 gelatinizing and apparently lacking. The Angiocarpous lichens of 

 many authors. 



KEY TO FAMILIES. 



Thallus with Pleurococcus or Palmetto, alga. 



Thallus crustaceous, without cortex Verrucariacea 



Thallus foliaceous or squamulose, cortex present Dermatocarpacea 



Thallus with Trentepohlia alga, crustaceous, the apothecia solitary or 

 sub-confluent but not forming stroma Pyrenulacea 



VERRUCARIACEJE. 



Thallus uniform crustaceous, growing upon or within the upper 

 layers of the substratum, without cortex, the gonidia of Pleurococcus or 

 Palmella algae: Apothecia single, erect r with an apical pore. 



I. Verrucaria(Web.)Th.Fr. 



Verrucaria Weber, Prim. Flor. Hols. p. 85. 



Verrucaria Th. Fries, Gen. Heterol. Europ. 109. 1861. 



Verrucaria A. Zahlbr., Ascolichenes, 54. 1907. 



Thallus crustaceous, rimose areolate, or powdery, commonly with 

 an evident hypothallus, rarely sorediate, usually upon the substratum, 

 rarely within. Apothecia entirely immersed, half sunken, or sessile; 

 perithecium coal-black, horny, globular, flask-like, or hemispherical 

 with the underside open; paraphyses soon gelatinizing; spores 8, 

 ellipsoid, oval, or globose, one-celled, colorless or rarely brown. 



About ico species, often difficult to define. 



