AMAUROCH^ETE 155 



an intricate network, very abundant, elastic, on fall of the peridium 

 appearing like tiny tufts of wool, the meshes large, but formed as in 

 Stemonitis, persistent, dull black; spores, under the lens, dull olivaceous 

 black, minutely roughened, 12-14 /x. 



This species differs from A. fuliginosa especially in the capillitial 

 characters. In the latter species the capillitial branches fray out, and 

 are only sparingly united into an extremely lax net. In the present 

 form the net is the thing common to the entire fructification. The 

 total effect is to lend to the blown-out aethalium a woolly appearance, 

 entirely unlike that of its congener under the same conditions. But 

 until fructification is quite mature, the presence of component spo- 

 rangia below is suggested by the papillose upper surface, and even 

 after maturity the suggestion of sporangia persists when viewed with a 

 hand lens. 



The amaurochsetes are remarkable in that they appear upon co- 

 niferous wood, logs or lumber, to all appearance undecayed. The 

 species just described developed abundantly in August on the recently 

 decorticated logs of Pinus ponder osa, on the southwestern slopes of 

 Mt. Rainier, Washington. In logging operations in the locality referred 

 to, the trees are felled often at a considerable distance from the mill. 

 The logs are dragged along the ground, the transportation facilitated 

 by removal of the bark from the new fallen trunk. In a few weeks' 

 time, affected by alternate rain and sun, the whole surface becomes 

 marked with hundreds of minute, almost invisible cracks, and it is 

 in the larger of these that the plasmodium of the present species has 

 its habitat. The plasmodia rise to fructification, scores at a time, 

 upon a surface, new and white, showing otherwise no evidence of any 

 decomposition. Doubtless the persisting cambium, the unused starches, 

 sugars, the wood of the season yet unlignified, afford easily accessible 

 nutrition. 



When this form was first examined in the laboratory its distinctness 

 was immediately seen. It was without doubt Fries' Lachnobolus 

 cribrosus. Under this name, citing Fries' description, specimens were 

 sent out to various herbaria. Further study of the records, however, 

 soon convinces one that we are here face to face with the species de- 

 scribed by Albertini and Schweinitz in their fine "Conspectus." Their 

 account of the form, evidently often taken and now described with 

 great care, is entirely clear when read in the presence of the facts. 

 The matter is discussed fully in North American Slime-Moulds, 

 2 ed., pp. 151 ff. 



Zukal (Verh. Zool.-Bot. Ges. Wien 35 : 335) describes A. speciosa 

 as a new species. This Saccardo writes down (Syll. Fung. 7 : 399) 



