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). 
(b) 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. 
(f) 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. 
