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Parmelia pertusa. Punctured Lichen. 



This rather rare species will be seen at times wherever P. 

 physodes is plentiful, either on mountains or in the pine bar- 

 rens, and can be recognized after a glance through the lens, for 

 though similar to that species in size and habit, it shows here 

 and there, usually in the middle of a branch or tip, a round or 

 oval hole less than 0.5 mm. in diameter. An observant person 

 will at once notice that these holes appear to be made by in- 

 sects, but as the punctured parts grow older, the edges of the 

 holes lose the appearance of having been gnawed, and look as if 

 formed in the growth of the lichen. Examination of the under 

 surface will show that patches of the black, spongy material 

 have been eaten off or tunnelled through, exposing the white 

 pith. 



While insects are probably responsible for this determining 

 character, there are other points on which P. pertusa differs 

 from P. physodes. The soredia, instead of being borne on fiow- 

 er-like tips, usually start as whitened lumps well back from the 

 tip and develop commonly into mushroom shape, with white 

 soredia on the top. 



Fruits are unknown in this region, but when found in the 

 tropics, the spores measure 45 to 60 by 22 to 28 microns, about 

 7 times longer than those of P. physodes. It is best therefore to 

 consider P. pertusa a distinct species. It will not be confused 

 with any other lichen, because no other is regularly punctured 

 in this fashion. (For detailed description and comparisons, see 

 P. physodes.) 



Parmelia colpodes. Black-Paw Lichen. 



Also called Anzia colpodes. Found on tree bark rather fre- 

 quently in the pine barrens, occasionally on mountains. Though 

 at first sight this fourth of the Shield Lichens with puffed tips, 

 looks like a darkened P. physodes, closer inspection will show it 

 to be entirely different — so different that some put it in a special 

 genus Anzia. It forms straggling rosettes 3 or 4 cm. across on 

 tree-bark, preferring oaks. The narrow main trunks divide into 

 broader branches and still broader tips, but few parts are broad- 

 er than 2 or 3 mm., while many are 1 mm. in thickness. The 

 olive-green or blackish main trunks (turning white in old her- 

 barium specimens) are often arched, and roughened with warts 



