158 HERRE 



a dark brownish or lurid gray, this obscured by the dense covering 

 of black isidia, so that the surface appears black; beneath pale 

 brown, tomentose; more or less sprinkled with white, concave cy- 

 phels. 



Sterile in America and rarely found fertile in Europe. 



On rocks, trees, dead wood, old fences, moss, and earth. Com- 

 mon at all elevations. A plant of world-wide distribution. 



3. STICTA LIMB ATA (Sm.) Ach. 



Lichen limhatus Smith, in Eng. Bot. 16: pi. 1104, 1802. 

 Sticta limhatus Ach. Meth, Lich. 280. 1803, 

 Sticta limhatus Tuck. Syn. N. Am. Lich. I: 100. 1882. 

 Sticta limhatus Herre, Proc. Wash. Acad. Sci. 7: 368. 1906. 



Thallus small, usually one-leaved; lobes smooth, rounded, broad, 

 the margin crenate or sinuous; confluent gray soredia abundant 

 along or near the margin; color in the field usually a glaucous green; 

 herbarium specimens vary from bluish or greenish drab or gray to 

 dull rufous brown; beneath covered with a pale brown fleece which 

 becomes darker centrally; white concave cyphels rather sparingly 

 present. 



Apothecia unknown. 



Not uncommon along the higher ranges, at an altitude of 2400 

 feet and above. A European species recorded in this country only 

 from Oregon and the Santa Cruz peninsula, and by Eckfeldt re- 

 corded from Labrador. 



PELTIGERACE^. 



Thallus expanded foliaceous, or reduced to stellate lobes sur- 

 rounding the apothecia; cortex on both sides or only above, the 

 thallus attached by rhizoids, these sometimes greatly developed, and 

 the under side tomentose; alga Palmella or Nostoc. 



Apothecia without margin, adnate to the thallus by their whole 

 under surface ; upon the under surface as well as the upper surface 

 of the plant; hypothecium clear; paraphyses simple; asci 2-8 sporous 

 or multisporous; spores colorless to brown, ellipsoid, spindle or 

 needle-shaped, 2-8 locular. 



