■:^S — 



Parjnelia per I at a. 



Parmei.ia terlata (L.) Ach. 

 (Fig. 1.) This species, while one 

 of the most common of the Par- 

 melias, is also one of the most 

 confusing to the novice, as it is 

 seldom found in fruit, and the ap- 

 pearance of the thallus closely 

 resembles certain Cetrarias and 

 Peltigeras. The thallus is much 

 expanded, very leaf like, gen- 

 erally smooth, but sometimes 

 crumpled, is greenish yellow, 

 gray green, slate color and even 

 light brown. Beneath it is black 

 with reddish brown margins ; these 

 turn back in such a manner that 

 they are often mistaken for apo- 

 thecia by the beginner. The lobes 



are not ciliated but are often covered with white soredia. Generally the 

 under surface is smooth but occasionally black fibrils are present. The 

 apothecia are large, the disk a greenish brown with entire margin, which 

 when fully developed splits down to the centre of the cup. Apothecia are 

 so rare that in a hundred specimens one in fruit may not be found. /'. 

 per lata is usually found on rocks, growing to a large size, often a foot in 

 diameter. Occasionally it is found growing on trees or old logs. 



Parmelia perforata (Jacq.) Ach. (Plate VI. 3 )— The thallus and gen- 

 eral appearance of this species closely resembles P. perlata, but can easily 

 be distinguished from it by the cilia with which the margins of the lobes are 

 covered: in some specimens they are very abundant, looking like a fringe of 

 hair. This seems to be especially marked in the P. perforata found in 

 the Southern States. The color is glaucescent, or blue sea green, with a 

 whitish bloom. Beneath it is black, frequently covered in places with a 

 bunch of black fibrils. The apothecia are abundant, and usually are very 

 large. The disk is a dark chestnut color, the margin thin and entire. At 

 the centre the apothecia are usually perforated, hence its specific name. It 

 is found on trees and rocks, more often fertile on trees. 



Parmelia crinita Ach. Thallus the same in color as /'. perjorata, the 

 lobes ciliated, but not so abundantly as in /'. perforata. The thallus is 

 usually densely covered with isidioid granules, or coral-like excrescences. 

 Beneath it is black and fibrillosc. The apothecia are not so common as in /'. 

 perforata: they are large and round, not perforated. While much like some 

 specimens of P. per lata it can be distinguished from it by the isidioid growth 

 on the upper side of ttie thallus, and the mat-like fibrils on the under side, 

 also by the cilia on the margins. Its habitat is trees and rocks; the thallus 

 of the rock form has usuallv finer cut lobes. 



