50 THELOSCHISTES. 



exs. n. 79. Physcia, Nyl. Syn. 1, p. 410, a. Xanthoria, Th. 

 Fr. Scand. p. 145. 



On trunks and stones near large bodies of water. Newfound- 

 land, Pylaie, 1826. New England, and New York, common. 

 Shores of Lake Superior, Agdssiz. San Diego, California, Dr. 

 J. Gr. Cooper. 



2(a). T. polycarpus (Ehrh.) ; thallus reduced, sub-orbicular, 

 now sub-stellate, but typically conglomerate, and complicate; 

 the much narrowed divisions many-cleft, concealed for the most 

 part by the very numerous smallish, sub-crenulate apothecia. 



Spores as in the last. Parmelia parietina,/., Fr. L. E. p. 73. 



Physcia, Tuck. Obs. Lick. I, I.e. p. 385. Physcia parietina, var. 

 3, Nyl. Syn. I, p. 410. Xanthoria lychnea, /9, Th. Fr. Scand. 

 p. 146. 



On trees and dead wood, in the northern and western States, 

 very common, Halsey (Parm. rutilans] View, 1823. British 

 America, Richardson. Alabama, T. M. Peters. Rocky Mount- 

 ains, Dr. Hayden. Santa Fe, Fendler. California, Wright. 



The North American lichen commonly larger than the European, 

 .and on the under side rather conspicuously, and now even mar- 

 ginally fibrillose ; but not otherwise really differing, even in the 

 widest lobed, sub-stellate Californian state. Nylander (Scand. 

 p. 108) remarks that a Scandinavian form of T. lyclmeus on dead 

 wood, seems sometimes to pass into the present; and Dr. Th. 

 Fries (Scand. p. 147) indicates Stenh. Lich. exs. n. 127, B, as an 

 instance of such transition. But I am unable to see anything 

 in the specimen just-cited, or in others exactly similar from Cal- 

 ifornia (Bolander) but the present sub-species; which, however 

 nearly approaching the narrower states of T. parietinus, it is 

 perhaps more natural to keep apart from it. 



2(b). T. lychneus (Nyl.) ; thallus reduced, sub-orbicular, sub- 

 stellate, or effuse, varying in colour as the preceding ; the linear, 

 many-cleft divisions at length more or less ascendant and gran- 

 ulose or powdery at the margins; apothecia rather infrequent, 

 smallish, margin entire or granulate. Spores as in T. parietinus. 



Physcia parietina, v. lychnea, Schcer., Tucker m. Obs. Lich. 



1, I. c. p. 386. Physcia lychnea, Nyl. Scand. p. 107. P. contro- 

 versy Mass., Koerb. Par erg. p. 38. Xanthoria lychnea, a, in 

 part, Th. Fr. Scand. p. 146. 



