SECT. m. MYXOGASTRES. 269 



could not remain erect were it not for the tubes of the 

 volva which contract on the stem and act as a sustain- 

 ing force. Thus these very revolting fragile plants 

 afford a very striking instance of mechanical power ex- 

 erted by vegetable matter. 



The Myxogastres are an anomalous group of fungi 

 which often appear as black or coloured spots on dead 

 leaves and twigs. Sometimes their mycelium or spawn 

 is large and conspicuous, as that of the Eeticularia 

 maxima, which overruns cucumber beds, choking up the 

 breathing pores, and killing the plants. Species of these 

 fungi are found upon mineral and vegetable substances 

 dead and alive, and the same species grows upon plants 

 of very different affinities, so that they depend upon the 

 atmosphere for their nourishment, and not on their 

 matrix. Like the puff-balls they end their lives in 

 myriads of microscopic dust spores, but they begin it as 

 a gelatinous mass, sometimes sparkling as a gem, bril- 

 liant with the metallic tints of gold, silver, steel, or 

 copper. 



The gelatinous or creamy mucilage of which these 

 fungi consist, forms a mycelium which is either diffuse, 

 or creeps over the matrix on which it grows in anasto- 

 mosing filaments like a network, or it is arranged 

 without any definite order. This spawn gives rise to 

 many bodies having an envelope of one or more concen- 

 tric membranes, technically called a peridium, enclosing 

 a gelatinous fertile substance which, when mature, be- 

 comes a mass of scales or threads mixed with spores ; the 

 spores are mostly attached to short threads singly or in 

 groups, sometimes surrounded by a firm coat or cyst. 

 These bodies are either sessile on the mycelium or 

 stalked, and are either free or confluent. In their soft 

 state the tissues are so delicate that they exhibit no 

 structure, but just as they are passing from the puffy 

 to the dry dusty state there are indications of it. 



