TORREYA 



Vol. 39 July-August, 1939 No. 4 



Guide to the Lichens of the New York Area — Part 3 

 G. G. Nearing 



Papery Lichens (Groups 5 to 12) 



Among the Papery Lichens, differences in form are some- 

 vvhat less obvious than among the Stalked Lichens. The aim of 

 this guide is to make possible the identification of a great many 

 species with no other aid than a hand-lens, but in order to give 

 a clearer idea of relationships, and to make determinations 

 more certain, microscopic characters are mentioned also and 

 given increasing prominence as the forms become simpler, the 

 obvious distinctive characters fewer. 



Papery Lichens are flattened to make an upper surface, and 

 an under surface different from it in structure and usually in 

 appearance. This under surface is sufhciently free from the foot- 

 hold so that it can be inspected and described. Stalked Lichens 

 (Groups 1 to 4) differ from papery Lichens in having some sort 

 of stalk, or in being lifted largely well clear of the foothold. 

 After an intermediate class of Flake Lichens (Group 13), the 

 Crust Lichens (Groups 14 etc.) differ from Papery Lichens in 

 having no free under surface, but adhering tightly to the foot- 

 hold or even growing within it. 



Key to the Papery Lichen Groups 



(This key will not be found entirely satisfactory, especially if no compound 

 microscope is available, and chief reliance should be placed rather on a careful 

 reading of the general description of each group, on the illustrations, and on the 

 references to similar species at the end of each specific description.) 



Algal cells not in chains 



Lichens bright yellow or orange, with yellow or or- 

 ange fruits Group 9 

 Lichens greenish gray, whitish, pale yellow, brown 

 or olive 

 Fruits chestnut-brown or greenish (yellowish gray 

 in Cetraria placorodia and Parmelia amhigua). 

 Spores undivided, colorless 



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