205 



Fruits brown or black, up to 4 mm. in diameter, with a thick, 

 smooth, drab rim, on the under side of which are often radiating 

 bristles, forming a fringe visible through a very strong lens. Spores 

 2-celled, brown, 14 to 32 by 7 to 12 microns. 



Physcia endochrysea, because so nearly the color of bark or 

 stones, is not often seen unless searched for. When found, a slight 

 scraping with the knife or fingernail reveals the brilliant color of 

 its pith. Since this species is common, scratch any small, dusky 

 rosettes until the orange pith is seen. If exactly similar rosettes 

 but with white pith are later found, these are the less common 

 P. obscura. A larger, pale form, also with white pith, but in most 

 other respects similar, is P. setosa, another subspecies. A lichen in 

 which the pith is dull yellow, is P. sorediata, drab with whitish 

 soredia. The only local Papery Lichen with a pith color to com- 

 pare with P. endochrysea, is the subspecies P. endococcinea, a 

 color form of P. setosa, having bright orange or orange-buff pith, 

 but usually with this shade showing also under some of the tips, 

 and even on some holdfasts. 



Physcia setosa. Bristly Lichen 



Found in the northern part of the New York area, and said to 

 -be common in parts of New England. As it is only a subspecies of 

 P. obscura, with no definite points of distinction, it may be inter- 

 preted freely or ignored. It grows somewhat larger, in rosettes up 

 to 10 cm. across, with larger and more luxuriant parts, sometimes 

 decorated with tiny lobes along the branches, when it approaches 

 P. hypoleuca, which it resembles in the whitish or ashy color of 

 the upper surface, but contrasts with in being black beneath. The 

 pith is white. A distinguishing feature is the fringe of bristles 

 under the fruit-rim, like that in P. obscura, but better developed. 

 Spores tend broader than in P. obscura, up to 30 by 17 microns. 

 It is interesting that P. setosa may grow intermingled with Cande- 

 laria fibrosa (Group 9), making a sharp contrast with the lemon- 

 yellow hue of that species, but in structure and size, including the 

 fringe of bristles, the two appear identical, dift'ering only in color 

 and in the spores. 



