224 PHYLUM VII. CARPOMYCETEAE 



sexual organs have not been discovered. The part of 

 the truffle that we eat is the large spore-fruit. These 

 are collected in Europe by experts and preserved for the 

 market, where they command high prices. 



Laboratory Studies, (a) Collect fruiting specimens of the 

 common fruticose lichen (Usnea), which grows upon branches 

 of trees in forests. Make thin cross-sections of the stem, mount 

 in alcohol, afterward adding dilute potassium hydrate. Study 

 the filaments and their relation to the algae. Isolate some of 

 the algae by tapping on the cover-glass, and note their resem- 

 blance to Green Slime (Protococcus). 



(6) Make thin vertical sections through one of the fruiting 

 disks, mount as above, and study asci, ascospores and para- 

 physes. 



(c) Collect some of the small, flat, many-lobed lichens which 

 grow on the bark of apple-, maple-, and oak-trees, and which 

 have small blackish fruit-disks. Make careful sections of the 

 plant-body through the fruit-disks, and study the whole struc- 

 ture, ascospores, asci, paraphyses, filaments, and algae. 



(d) Search for cup-shaped fungi, in the spring, about old 

 hot-beds and upon well-rotted barnyard-refuse. A common 

 cup fungus of an amber color often to be met with in such 

 localities is one of the best for the study of ascospores and asci. 

 Make very thin sections at right angles to the inner surface. 



(e) Collect the bright red saucer-shaped cup-fungus (Sar- 

 coscypha coccinea) growing in the woods upon decaying sticks 

 and having a diameter of 1 to 4 centimeters. Make similar 

 sections. 



(/) Collect a few Morels (Morchella esculenta), and make 

 sections at right angles to the surface of the pits which cover 

 the upper portion and examine for ascospores and asci. 



(g) Collect fresh specimens of Plum Pockets, and preserve 

 them in alcohol. Study the fungus by making very thin 

 sections at right angles to the surface. Each ascus will be 

 found to contain several rounded ascospores. 



(h) Collect Slit-fungi (Hysterographium) on the bark of oak 

 or ash trees, or on dead twigs of sumach, and other shrubs. 

 The apothecia are black and carbonaceous, and are about a 

 millimeter long. 



