226 PHYLUM VII. CARPOMYCETEAE 
the microscope add iodine, which will stain the starch-grains 
blue or purple, and the yeast-plants yellowish. Many of the 
latter will be found in process of budding. 
(q) Repeat experiment g on page 103 for production of 
carbon dioxide by yeast. 
(r) Spread a little ‘‘compressed”’ yeast on a fresh-cut slice 
of potato or carrot; cover with a tumbler or bell-jar to keep it 
moist; after a few days (four to eight) examine for cells which 
are producing ascospores. 
(s) Commercial Truffles are natives of Europe, but they may 
be obtained for study in our markets. Make thin cross- 
sections of the large spore-fruit and examine the ascospores and 
asci. 
Cuass 15. BASIDIOSPOREAE 
THe BasipIumM FUNGI 
374. The plants, or rather the fruits, of this class are 
among the largest and most conspicuous of the fungi. 
They are mostly saprophytes whose abundant vegetative 
filaments (mycelium) ramify through the nourishing sub- 
stance, and afterward give rise to the conspicuous spore 
fruits. The spores are produced usually in 4’s upon 
slender outgrowths from the ends of enlarged cells (ba- 
sidia), the latter usually arranged parallel to each other 
so as to form a spore-bearing surface (hymenium), which 
may be external (as in Toadstools) or 
internal (as in Puff-balls). 
375. The basidia in this class are 
here regarded as homologous with the 
asci of the Ascosporeae. The differ- 
ence between them is that in the asci 
ome af basidie P| the spores in their development remain 
pena inside of the ascus cavity, while in the 
basidia the spores as they develop push out so as finally 
to become external. It is obvious that the ascus is the 
