MYXOMYCETES 



337 



Fig. 288. — Plasmodium of a Myxo- 

 mycete growing on wood. X about i. 



(meaning slime) and myces (meaning mold or fungus) {Fig. 288). 

 This naked mass of protoplasm is called a Plasmodium. It is a 

 semi-liquid and is found flowing out of the cracks of rotten logs 

 and stumps, forming white or colored doughy-like masses. They 

 are often found creeping out of the cracks of old plank walks, out 

 of decayed bark, or out of 

 apple pumice around a cider 

 mill. Some of the Myxomy- 

 cetes are parasites, living in 

 the tissues of higher plants 

 and often causing much in- 

 jury. 



The Plasmodium is multi- 

 nucleate and is able, by put- 

 ting out and withdrawing regions of its body, to move about like 

 a gigantic Amoeba. Sometimes the Plasmodium" breaks up into 

 many smaller portions which are able, by means of cilia or flagella, 

 to move about like the low forms of animals. The Myxomycetes 



have the characteristics of both 

 plants and animals, and opin- 

 ions differ as to whether they 

 should be classed as plants or 

 animals. 



Their method of obtaining food 

 consists chiefly in digesting tho 

 substances found in other 

 plants. Those forms which 

 live on dead organisms are 

 able to utilize the carbohy- 

 drates remaining in decaying 

 organic matter, while those 

 attacking living plants prey 

 upon the tissues of the plant 

 attacked. Those forms living on dead organisms are called sapro- 

 phytes, while those forms living on living organisms are called 

 parasites. The living organism attacked is called the host. 



Reproduction in the Myxomycetes is asexual. The first indi- 

 cation of reproduction in most of the saprophytic forms is the 

 appearance of upward projections on the surface of the Plas- 

 modium. Into these projections, which are at first hollow 



Fig. 289. — A, Myxomycete, 

 Stemonitis, in which the Plasmodium 

 has been transfonned into slender 

 stalked sporangia (sp) which bear 

 numerous spores (s). 



