FUNGI, THE LICHENS 



3 OI 





overtop the asci and broaden out, thus 

 forming a covering (epithecium) over 

 the ends of the asci.* Parmelia is 

 another very common foliaceous 

 lichen growing on rocks, sometimes 

 very common on small stones in the field. Peltigera 

 is a common one growing on leaf mold in the 

 forest. 



449. The fruticose lichens. These are more 

 or less erect forms and often very much branched. 

 Some species of Cladonia grow on rotting wood, 

 and one species with bright red rounded tops is 

 very common on rotten stumps and logs The 

 bright red bodies are the fruit bodies (apothecia), 

 which here are arched instead of cup-shaped. 

 Another species of Cladonia (C. rangiferina) is the 

 reindeer moss. It is profusely branched into 

 slender grayish green branches. It is very com- 

 mon on the ground of the arctic tundra, sometimes 

 covering extensive areas. It is eaten by the rein- 

 deers. Another common fruticose lichen is the 

 "hanging moss" of the Northern States (Usnea 

 barbata), often found hanging from the limbs of 

 trees in damp or swampy woods. It consists of 

 very fine, grayish, much-branched threads, some- 

 times reaching a length 20 cm. to 30 cm. or more, 

 but usually smaller. It should not be confused 

 with the "hanging moss" (Tillandsia) of the Southern States, 

 which is a flowering plant. 



450. Crustaceous lichens. These form thin and very close 

 incrustations on rocks and the trunks of trees. They are often 

 so closely connected with the rock or bark that it looks as if the 



* The fruit body of the lichen is the apothecium. The sterile wall out- 

 side of the group of asci is the excipulum; the broadened ends of paraphyses 

 united above the asci form the epithecium; the tissue beneath the asci is the 

 hypothecium. 



HK- 251. 



Lichen (Usnca 



barbata), often 



called hanging 



