140 
Mycologia 
Three years later, Fischer (4) published his work on the de- 
velopment of Armillaria mucida, in which he observes that the 
hymenial primordium has an endogenous origin, but that the 
primordium of the pileus precedes the appearance of that of the 
hymenium. 
In 1911, Beer (3) followed with his notes on some species of 
Agaricaceae. In his work upon Hypholoma fasciculare, he prac- 
tically confirmed what Allen (1) had already reported for Hy- 
pholoma, while in Armillaria mellea he found the sequence of the 
differentiation of parts and their development to correspond very 
closely with Atkinson’s observations upon Agaricus campestris. 
During November, 1912, specimens were collected on the cam- , 
pus of the University of Washington. No trouble was ex- 
perienced in finding all stages from the youngest to the fully de- 
veloped carpophores. The mycelium in the form of white, silky 
rhizomorphs was found just under the surface of the decayed 
organic matter on a moss-covered log of Alnus oregana. The 
rhizomorphs measure about 0.5-1 cm. in diameter. The pure 
white buttons were easily obtained from the surface of this sub- 
stratum. Several mature carpophores aided much in locating the 
tiny button forms, which were readily identified by their viscid 
upper surfaces. Buttons 1-5 mm. in diameter, and portions of 
more mature carpophores were fixed in chromo-acetic acid and 
were carried through alcohol and xylol into paraffin. The sec- 
tions were generally cut 6 /x thick. In staining, the best results 
were obtained with acid fuchsin and picric acid, to bring out the 
early differentiations. The safranin, gentian-violet, and orange 
combination was used to advantage in older stages. A large num- 
ber of slides were made and the accompanying plates were photo- 
graphed from slides chosen from these. 
The early stage of the carpophore is an undifferentiated mass 
of interwoven hyphae which reaches a height of about 1.5 mm. 
At this time it is about 1 mm. in transverse diameter. Figure 1 
shows the earliest stage. Over the surface of this primordial 
carpophore there is a layer of coarser, more loosely arranged 
hyphae. This is the universal veil. For the most part, the hyphae 
of the interior extend vertically from the base where the carpo- 
phore is connected with the rhizomorph. Sections of the latter 
