344 
MICHAEL LEVINE 
noticed that the fungus appears at first in the form of a small white 
sphere in which a brown-colored central portion, the future pileus, 
is clearly differentiated. His description of the formation of the 
lamellae does not in any way differ from his previous description of 
other angiocarpous forms. The next work of importance that fol- 
lowed Hoffmann's was that of De Bary (1866), who also studied the 
development of Agaricus campestris, A . (Pholiota) praecox and Coprmus 
micaceus. He held that the young carpophore begins as a mass of 
delicate hyphae of uniform diameter densely interwoven. De Bary 
does not describe the growth direction of the hyphae. Very early 
this nodule becomes divided into two parts by the formation of a 
horizontal annular cavity which appears in longitudinal section as two 
openings in the upper and inner portion of the undifferentiated mass. 
The region lying above a horizontal plane through this cavity forms 
the pileus while that below forms the stipe. The hyphae which form 
the margin of the pileus are continuous with the superficial cells of 
the stipe. The layer of hyphae directly above the gill chamber grows 
into it and forms the lamellae. In Coprinus micaceus and C. fimetarius 
the lamellae grow into the gill chamber and in the fully developed 
carpophore are found in contact with the stipe. De Bary's figures of 
C. micaceus clearly show in young stages the edges of the gills in 
contact with the stipe, though he does not emphasize their connection 
with it. For Amanita muscaria and A. rubescens De Bary observed 
that in buttons somewhat more than 10 mm. long the hymenium and 
the lamellae in general are already formed and that the lower and inner 
margins of the lamellae are continuous with the tissue of the stipe 
just as the upper margins are continuous with the substance of the 
pileus. 
R. Hartig (1874) practically accepts Hoffmann's views as to the 
origin of the stipe and pileus. In Agaricus (Armillaria) melleus he 
finds that the lower surface of the pileus forms an exposed hymenium. 
A vigorous downward growth of the hyphae now sets in from the upper 
surface and margin of the pileus and a corresponding upward growth 
of the superficial hyphae of the stipe thus forming a weft of hyphae 
or a veil hiding from view the hymenium. This differs from Hoffmann's 
view only in that the hymenium is formed superficially. De Bary 
(1884) ten years later was misled into accepting Hartig's view as true 
for a large number of further types. Atkinson (1914^) has recently 
reinvestigated this form and found that in Armillaria mellea as in 
