ON THE CULTIVATION OF MYCETOZOA FROM SPORES / 



spread over the new. Every morning a fresh supply of Stereum 

 should be placed in front of, and touching, the piece over which 

 the Plasmodium is advancing, so that it shall not go back on the 

 exhausted fungus. In this way the growth may be led round the 

 plate, the old pilei are cleared away behind, and fresh added in 

 front until the cultivation has reached the desired dimensions, when 

 it can be dried by exposure to the air to form a fresh store of 

 sclerotium. 



If, however, it is desired that the plasmodium should form into 

 sporangia, the supply of food is stopped. If this is done without 

 taking any further precaution, it is often found that the plasmodium 

 becomes poisoned by returning to the old fungus, now loaded with 

 decomposing refuse-matter, and it produces imperfect sporangia or 

 dies. Though this is not always the case, yet to insure perfect de- 

 velopment the following method is found to give good results. 

 A pile of well-washed thick sticks, with the bark on them, is placed 

 under a bell- jar, and the Stereum, on which the plasmodium is 

 growing, is laid on the pile ; it is as well to add a few pilei at first, 

 that the shock of removal may be recovered from ; the plasmodium 

 soon leaves the Stereum, and wanders over the sticks ; there it frees 

 itself from impurities, and, finding nothing to feed upon, it changes 

 to perfect sporangia in four or five days. 



Another cultivation of considerable interest is that from the 

 spores of a possibly new species, which I have named provisionally 

 Didyynium comatum, from the abundant straight threads of which 

 the capillitium is composed. It was found in March, 1899, growing 

 in company with Dldnmium diffonne Duby on old fronds of hart's- 

 tongue fern on the Undercliff at Lyme Regis. It is no doubt nearly 

 allied to D. diffonne, and may prove to be merely a variety of it. It 

 is most difficult to distinguish between the two forms in the field ; 

 in both the egg-shell-like crust may be removed entire from the 

 iridescent membranous inner sporangium-wall, though sometimes 

 the two layers are closely adhering ; in D. comatum, however, the 

 crystals forming the outer crust are often more stellate and less 

 densely compacted than in D. dlfforme. In the first gatherings 

 there was a marked difference between the spores of D. comatum and 

 those of its ally ; they were paler and smaller ; they contracted into 

 a boat-shape when placed in Hantsch's fluid or spirit, in consequence 

 of one side being thinner than the other, as do also the spores of 

 D. diffonne ; yet they lacked the dark branching lines usually present 

 on the contracting side of the spores of the latter species. Gather- 

 ings of D. comatum in April, 1900, from the Lyme Undercliff 

 exhibited spores similar to those above described ; but another 

 gathering of the species from a straw-yard in an open field at 

 about the same date showed profuse slender capillitium, but had 

 spores that could not be distinguished from the normal spores of 

 D. diffonne. 



The difference between the two forms resolves itself therefore 

 into the structure of the capillitium, and in the behaviour under 

 cultivation to be noticed in the following account : The capillitium 

 of D. diffornii is sca,Qty, aid cm^isbs of stout and usually separate 



