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 COLOSTOMA 



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 endoperidlum, 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. 



Cai-6s'-t6-mS 



131 



