204 



Fruits black, brown or frosted white, up to 2 mm. in diameter, 

 with a smooth or broken, whitish rim. Spores 2-celled, brown, 

 12 to 22 by 6 to 10 microns. 



Physcia hispida can be definitely determined by one glance at 

 the illustration. The puffed and bhstered tips, bursting open, have 

 a distinctive character easily recognized. The somewhat similar 

 P. comosa (Group 4), with longer hairs, does not burst its tips, 

 but bears bell-shaped fruits there, while the fruits of P. hispida 

 occur along the branches, far from the tips. The puffed Parmelias 

 (Group 5) have no hairs above, and are dark beneath, P. physodes 

 alone bursting its tips, but in a different manner. No other lichens 

 resemble Physcia hispida, unless P. tenella and P. ascendens are 

 considered separate species. 



Physcia obscura. Dark Blister Lichen 



Found throughout the New York area on trees and rocks, espe- 

 cially in shaded places. Frequent. Much more common, and dif- 

 fering only in internal color, is P. endochrysea, really only a variety 

 of P. obscura, but well enough known locally as a species, to justify 

 retaining that rank here. P. obscura is white within, P. endochrysea 

 bright blood-orange, as shown where scratched or broken, or where 

 eaten by insects, which are particularly fond of herbarium speci- 

 mens. For description and comparisons, see P. endochrysea. 



Physcia endochrysea. Orange-Pith Lichen 



Also called P. obscura var. endocJirysea. Growing on tree-bark 

 everywhere, also on rocks and over moss in shaded places. One of 

 our most common lichens, but escaping attention because of its 

 dull color. Rosettes usually 3 or 4 cm. across, or running together 

 to cover an indefinite area. The branches and lobes, 1 mm., or at 

 most 2 mm. wide, remain close to the foothold, the central parts 

 often running together in a confused mass, with heaps of pale green 

 or gray soredia, irregularly 1 mm. or so across, or massed into a 

 sorediate crust 2 to 3 mm. thick. There are sometimes also in- 

 crustations of blackish granules. The upper surface is dull drab 

 when dry, dusky green when wet, the under surface black, with 

 many black holdfasts, densely spreading, and commonly showing 

 from above as a fringe. The pith is blood-orange. 



