212 HERRE 



I. EVERNIA PRUNASTRI (L.) Ach. 



Lichen prunastri Lmne, Sp. VlsiTit. 2: 1147. 1753. 



Evernia prunastri Ach. Lich. Univ. 442. 1810. 



Evernia prunastri Tuck. Syn. N. Am. Lich. I: 39. 1882. 



Evernia prunastri Herre, Proc. Wash. Acad. Sci. 7: 342. 1906. 



Thallus tufted, fruticose, erect or pendulous, angular or flattened; 

 branches numerous, narrow to linear, elongate; or (forma soredifera 

 Ach.), shorter and much wider lobed, beneath lacunose or channel- 

 led; white or greenish, with mealy, lateral, and confluent soredia 

 very abundant ; these also more or less present in the typical form ; 

 color whitish, pale green, to dark green; beneath much paler, often 

 white. 



Sterile with us. 



A very common lichen throughout, growing on trees, shrubs, dead 

 wood, fences, roofs, mossy stones; often forming conspicuous whitish 

 tufts on twigs of shrubs. 



Of very wide distribution, being found in Europe, Asia, Northern 

 Africa, and North and South America. 



LIII. Letharia (Th. Fr.,) A. Zahlbr. 



Evernia sect. Letharia Th. Fr. Lich. Scand. 1 : 32. 187 1. 

 Letharia A. Zahlbr. Ascolichenes, 218. 1907. 



Thallus tufted, erect or pendulous, attached by a holdfast, much- 

 branched, alike on all sides, the cortex of hypha^ perpendicular to the 

 surface; medulla cobwebby, with more or less firm medullary cords 

 or longitudinal threads, much as in Ramalina. Apothecia as in 

 Evernia. 



Species tew, of cool and temperate parts of the northern hemi- 

 sphere. 



I. LETHARIA VULPINA (L.) Wainio. 



Lichen vulpinus L'mne, Syst. Nat. ed. 10. 2: 1343. 1753. 

 Letharia vulpina Wainio, 

 Evernia vulpina Ach. Lich. Univ. 443. 18 10. 

 Evernia vulpina Tuck. Syn. N. Am. Lich. I: 38. 1882. 

 Evernia vulpina Herre, Proc. Wash. Acad. Sci. 7: 341. 1906. 

 Thallus tufted, erect, much-branched, becoming long and pendu- 



