The Myxomycetes of Eastern Iowa. ioi 



tissues of rotten stumps and logs. In such a situation the 

 protoplasm spreads over all moist surfaces, creeps through 

 the interstices of the rotting bark, spreads between the cells, 

 between the growth-layers of the wood, runs in corded vein- 

 like nets between the wood and bark and finds in all these 

 cases nutrition in the products of organic decomposition. 

 Such a Plasmodium may be divided, and so long as suitable 

 surroundings are maintained, each part v»'ill manifest all the 

 properties of the whole. Parts of the same plasmodium will 

 even coalesce again. If a piece of plasmodium bearing wood 

 be brought indoors, be protected from dessication by aid of a 

 moist dark chamber, not too warm, (70- F.) the organism 

 seems to suffer little if any injury, but will continue for days 

 or w-eeks to manifest all the phenomena of living matter. 

 Thus, under such circumstances, the plasmodium will con- 

 stantly change shape and position, can be induced to spread 

 over a plate of moist glass and so be transferred to the stage 

 of a microscope, there to exhibit in the richest and most inter- 

 esting and abundant fashion the streaming protoplasmic cur- 

 rents. As just indicated the plasmodia follow^ moisture, creep 

 from one moist substance to another, especially follow nutritive 

 substrata. They seem also to secure in some way exclusive 

 possession. I have never seen them interfered with by hyphce 

 or enemies of any sort, nor do they seem to interfere with 

 one another. Plasmodia of two common species, Heniiarcyria 

 clavata and H. riibiformis are often side by side on the same 

 substratum but do not mix, and their perfected fruits presently 

 stand erect side by side, each with its own characteristics, 

 entirely unaffected by the presence of the other. 



Under certain conditions, low temperature, lack of moisture, 

 the Plasmodium may pass into a resting phase, when it masses 

 itself in heaps and may become quite dry in lumps of consid- 

 erable size, and so await the return of favorable conditions 

 when former activity is quickly resumed. Sometimes the 

 larger plasmodia pass into the resting phase by undergoing a 

 very peculiar change of structure. In ordinary circumstances 



