FUNGI. 73 



spreads out so as to expose the spore sacs as they discharge their con- 

 tents (Fig. 43, D). 



Of the larger cup fungi, those belonging to the genus Peziza 

 (Fig. 43, H) are common, growing on bits of rotten wood on 

 the ground in woods. They are sometimes bright scarlet or 

 orange-red, and very showy. Another curious form is the 

 morel (Morchella), common in the spring in dry woods. It is 

 stalked like a mushroom, but the surface of the conical cap is 

 honeycombed with shallow depressions, lined with the spore 

 sacs. 



ORDER Lichenes. 



Under the name of lichens are comprised a large number of 

 fungi, differing a good deal in structure, but most of them not 

 unlike the cup fungi. They are, with few exceptions, parasitic 

 upon various forms of algae, with which they are so intimately 

 associated as to form apparently a single plant. They grow 

 everywhere on exposed rocks, on the ground, trunks of trees, 

 fences, etc., and are found pretty much the world over. Among 

 the commonest of plants are the lichens of the genus Parmelia 

 (Fig. 44, A), growing everywhere 011 tree trunks, wooden 

 fences, etc., forming gray, flattened expansions, with much 

 indented and curled margins. When dry, the plant is quite 

 brittle, but on moistening becomes flexible, and at the same 

 time more or less decidedly green in color. The lower 

 surface is white or brown, and often develops root-like proc- 

 esses by which it is fastened to the substratum. Some- 

 times small fragments of the plant become detached in such 

 numbers as to form a grayish powder over certain portions of 

 it. These, when supplied with sufficient moisture, will quickly 

 produce new individuals. 



Not infrequently the spore fruits are to be met with flat 

 discs of a reddish brown color, two or three millimetres in 

 diameter, and closely resembling a small cup fungus. They 



