Nichols— BinucUated Cells in Some Basidiomycetes. 39 
which had developed spontaneously in nature. During the win¬ 
ter specimens of Hypholoma perplexum appeared on an oak Jog 
in the green house. The rotten pieces of wood were broken away 
exposing an expanded sheet-like rhizomorph or perhaps sclerot- 
ium, with some young fruit-bodies just forming. A sharp dis¬ 
tinction between rhizomorphs and sclerotia probably cannot-be 
made. Between the round tuber-like sclerotium of Coprinus 
ephemerus and the long branched mycelial strands of Armillaria 
mellea are many intermediate forms, among which are the sheet- 
like mycelial masses of Hypholoma perplexum. These have an 
outer layer of hard brown cells and a central mass of thin wailed 
hyphae bearing, perhaps, a closer resemblance to the structure 
of the sclerotium than to that of rhizomorphs. But the sheet-like 
masses do not have any definite shape and, as far as this ma¬ 
terial showed, may be unlimited in their growth—characteristics 
not usually associated with a sclerotium. The central portion 
of this hyphal mass is formed of parallel hyphae which do not 
show any protoplasmic contents. Their walls have become gel¬ 
atinous and in the triple stain become light blue. Near the sur¬ 
face on each side there is a layer of thin walled hyphae with ir¬ 
regular cells. The cells are very closely packed together form¬ 
ing a pseudoparenchyma. On the outer surface there is a layer 
formed by small closely packed cells which are filled with a hard 
brown substance. When a carpophore is to be formed some of 
the thin walled hyphae force their way through the hard outer 
layer where they unite to form the carpophore. Occasionally 
the carpophores are formed singly but they are usually in 
clusters. 
Closer examination shows that the thin walled hyphae just 
beneath the surface of hardened cells are formed of short irreg¬ 
ular cells that contain very little granular cytoplasm. They are 
regularly binucleated. The nuclei are large, with a distinct 
nuclear membrane and a small nucleole. The chromatin does 
not appear as granular as in the majority of nuclei but takes a 
uniform light blue stain. The two nuclei are usually pressed close 
together near the center of the cell. In forming a carpophore 
a number of the thin walled hyphae force their my through the 
outer crust, branch profusely at the surface and spread out 
