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various species of Cladonia (Group 1), some of which take a 

 brown color. As these are very common, a little observation will 

 separate them from C. Fendleri, which is rare, and of quite dif- 

 ferent structure. 



Cetraria aleurites. Grizzly Shield Lichen. 



Also called Parmeliopsis aleurites. A common species found 

 especially on pine bark, rails and dead wood, in swamps, pine 

 barrens and hills everywhere. It forms a grayish white rosette 

 flat against the foothold, with branches and lobes radiating to 

 a total spread of 5 cm. or more, but is often fragmentary. 

 Branches may be 2 or 3 mm. wide, but the usually short tips, 

 less than 1 mm. wide, are sometimes divided into feathery lobes 

 less than 0.1 mm. wide. Scattered over the dry-looking upper 

 surface are minute white or yellow-gray granules, becoming 

 very numerous toward the center and extending into prongs or 

 coral-like growths. Eventually the center becomes a mass of 

 these growths, heaped into a cracked and humped crust, which 

 may occupy almost the whole lichen, making it necessary to 

 look sharply for the few scraps of papery lobes around its edge. 

 The under surface is white to pale brown, and somewhat 

 wrinkled, with a few small, brownish holdfasts. 



Fruits on the typical form are hardly to be found, at least 

 in the New York area. There are however forms intermediate 

 between this species and C. placorodia, having the coral-like 

 growths few and scattered instead of massed in a central crust. 

 These forms are sometimes called var. diffusa, and they often 

 bear fruits much like those of C. placorodia, with similar spores. 



Though variable, Cetraria aleurites will be recognized with 

 ease by its white or silver-gray color, and the yellow-gray gran- 

 ular center. Other common Papery Lichens have similar 

 massed granules and coral-like growths, notably Parmelia rudec- 

 ta (Group 6), a lichen with typically much broader parts, rather 

 regularly speckled with small, flat, white soredia. Parmelia 

 frondifera, an uncommon form of P. saxatilis, has the growths 

 flattened into small lobes, and is distinguished by its black un- 

 der surface. Physcia stellaris and P. granulifera (Group 8) often 

 have central granules, but the frequent gray or blackish fruits 

 contain blackish, 2-celled spores. 



Cetraria aleurites, C. placorodia and Parmelia ambigua have 



