—44— 



Cetraria Aurescens. Tuctm. (Fig. 4.) This 

 beautiful lichen is found on coniferous trees. C^ 



The delicate green of the thallus, growing usually \^_ 

 in round mats with the bright chestnut colored \^ 

 apothecia massed together, some tiny and cup 

 shaped, others large and flat with crenulate mar- "°N^"^0 



gfins, makes a very handsome picture on the 



branches of old hemlock trees. Fig- 4- C. aurescens x I. 



The thallus is foliaceous and flat. The lobes are narrow and many cleft, 

 with crisped margins. Beneath it is white with many fine soft fibrils of the 

 same color, giving it a woolly appearance. The apothecia are on the margin 

 of the inner lobes of the thallus. The outer edges of the thallus are usually 

 free from apothecia. The disk is a light reddish brown. 



''^^-W 



Fig. 5. C. nriui/is x I. 

 Apothecia are very rare, 

 in color are reddish yellow. 



Cetraria Nivalis (L.) Ach. (Fig. 5-) The 

 "Snow Lichen" is a mountain species, found 

 on earth. The thallus is tufted, rather erect. 

 The lobes are many cleft and are somewhat 

 channeled, but not turned inward as in C. 

 cucullata. It is straw color, a little darker at 

 the base, which is smoother than the upper 



part of the thallus. 



They are larger, with crenulate margins and 



Cetraria gi.auca. (L.) Ach.— Some forms of Parinelia perlata are so 

 like C. glauca that it is difticult to distinguish them by the thallus ; then as 

 the apothecia are very rare it makes the problem more difficult. C. glauca 

 adheres to the substratum more closely than P. perlata. The latter usually 

 has a more robust appearance and is found on rocks. C. glauca occurs on 

 rocks, but more generally on trees. The upper surface of the thallus is a 

 light straw color, below it is black and smooth. The ragged edges of the 

 lobes are usually covered with soredia. Apothecia, when present, are large, 

 subterminal, disk chestnut color with rough margins. 



Cetraria glauca (L) Ach. var. STENorHVLLA, is found also in the 

 mountains. The upper surface of the thallus is a grayish white, beneath it is 

 black, but as the lobes turn over the effect on both sides is black and white. 

 The lobes of the thallus are narrower than in C. glauca and are thickly cov- 

 ered with coral-like soredia. 



Cetraria aculeata (Schreb.) Fr. Thallus much tufted and fruticose, 

 erect and very brittle, with spine-like branches which are covered with spin- 

 ules. The color is a dark brown and the surface looks polished. In appear- 

 ance it is much like a Cladonia. Apothecia are very rare. They are a little 

 darker than the thallus and on the margins are fine spinules. 



