Genus Calostoma 
weather is wet, the lining of the points of the star become gelati- 
nous and lie flat on the ground, anchoring the plant firmly ; but 
when the weather is dry, the soft, gelatinous part becomes hard 
and rigid, and curls the segments up around the inner ball; then 
the wind rolls it about, and it scatters its spores from the hole in 
the apex of the ball as it rolls. It is a fair-weather traveller, 
always resting at night and on damp days. 
GENUS CALOSTOMA 
This genus has but three known American species. The 
plants are remarkable in structure and substance. The spore 
mass or gleba lies at the centre of a base, and is in its young 
stages surrounded by four layers. The outermost coat is gelati- 
nous, and soon disappears. This is known as the volva or 
wrapper. The layer just within the wrapper also soon disap- 
pears ; it is known as the exoperidium. The layer just within 
the exoperidium is known as the endoperidium, and is the layer 
seen on the exterior of older specimens. Between the exope- 
ridium and endoperidium is a layer of red threads, part of which 
is torn away when the exoperidium breaks, and a part of which 
remains as a red star at the apex of the ball. 
The exoperidium is cartilaginous ; it is thin and fragile when 
dry, but when wet it is flexible, translucent, and soft. The 
endoperidium is hard and rigid when dry, and is conspicuous for 
the brilliant red which shows at its mouth. Within the endo- 
peridium is a sac which contains the spores; when the spores 
are mature, this sac contracts, and forces the spores out into the 
air. The mycelium, or vegetative part of the Calostoma plant, is 
composed of numerous cord-like fibres, translucent, jelly-like, 
and tough, which, branching and anastomosing into a dense net- 
work, form a rooting columnar base to the spore-bearing part of 
the plant. The name Calostoma means beautiful mouth, referring 
to the red star which surrounds the opening through which the 
spores escape. 
Cal-ds'-t6-m4 
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