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LABORATORY STUDIES 231 
Fungi (Tremellales) and the still more reduced Exoba- 
sidiales are probably to be placed here. 
Laboratory Studies. (a) Collect specimens of puff-balls in 
various stages of growth. Make very thin sections of the young 
spore fruit, and look for the cavities lined with spore-bearing 
cells (basidia). 
(6) Mount in alcohol some of the dust which escapes from a 
dry puff-ball. Examine with a high power, and note the spores 
and fragments of broken-up filaments. 
(c) Dig up the earth under a cluster of young puff-balls, and 
observe the vegetative filaments. Examine some of these 
filaments under the microscope. 
(d) In the summer look for Earth Stars (Geaster) in which 
the outer peridium is rolled back (open) when wet, and closed 
when dry 
(e) Stalked Puff-balls (Tylostoma) may often be found with 
a stalk 3 to 10 or more centimeters long holding the spore 
cavity aloft. 
(f) Look for Bird-nest fungi in fruit on sticks and twigs on 
damp ground. Note that when young the fruits are closed 
and solid, and that as they become older much of the internal 
tissue deliquesces, leaving the little egg-like spore packets. 
(g) Collect specimens of Stink-horns in various stages of 
development and preserve in formalin. Make vertical sections 
of the immature (globose) spore fruit and note the circular 
spore layer. Study the basidia and basidiospores under a 
high power. 
(hk) Collect a few toadstools in various stages of development, 
securing at the same time some of the subterranean vegetative 
filaments. Note the appearance of the young spore fruits, 
and how they develop into the mature toadstool. 
(t) Select a mature (but not old) spore fruit with dark- 
colored spores, cut away the stem, and place the top (pileus) 
on a sheet of white paper, with the gills down. In a few hours 
many spores will be found to have dropped from the gills upon 
the paper; these are the so-called ‘‘spore-prints’’. 
(j) Examine the minute structure of various parts of the 
spore fruit and the vegetative filaments, and observe that they 
are composed of rows of cylindrical colorless cells joined end to 
end, 
