TORREYA 



Vol. 38 March-April, 1938 No. 2 



Common species of the Mycetozoa 

 Robert Hagf.lstkin 



The fruiting bodies of the Mycetozoa, Myxomycetes, or 

 slime molds appear abundantly about the middle of June, and 

 continue throughout the summer and autumn until cold weather 

 sets in. They are spore carriers, and develop from a creeping, 

 feeding, growing slime called the plasmodium, which is gen- 

 erally regarded as an animal. The plasmodium is formed from 

 small animal-like bodies germinated from the spores under 

 favorable conditions of warmth and moisture. Plasmodia that 

 have not gone into fruit with the approach of freezing tempera- 

 ture will change themselves into a hardened substance called 

 sclerotium, in which inactive condition they will survive the 

 winter, reviving in the early spring and, after a certain period, 

 forming the first fruiting bodies. Often, during the winter in 

 mild weather, these revivals will come and fruitings develop. 

 After the first revival in the spring, the complete cycle will be 

 repeated during the warmer months, and, in many species, 

 several times. 



The Plasmodia feed mainly upon bacteria of decaying vege- 

 table matter. The fruiting bodies may therefore be sought on 

 old logs, leaves, ground debris, rubbish piles, and similar habi- 

 tats that are in a moist condition giving rise to sufficient bac- 

 terial food. They are fragile, and when collected should be 

 pinned into old cigar boxes into which a layer of corrugated 

 cardboard has been pressed. On arrival home the specimens 

 should be thoroughly dried with the addition of a small amount 

 of ordinary napthaline flakes to avoid the ravages of insects. 

 After that they may be trimmed and glued into small boxes, 

 and will keep indefinitely. 



The fruiting bodies exhibit great diversity in shape and color 

 among the different species, and are very beautiful under the 

 microscope. There are three general forms of fructification. The 



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