ADAMS: ORIGIN OF LAMELLAE IN SCHIZOPHYLLUM 827 
menial and sub-hymenial layers contracting much more strongly 
in the vertical direction than those of the tramal layer." 
There is no clear account of the early stages of gill formation 
in the literature and I have undertaken to fill this gap by the 
present study. The nature of the whole carpophore also becomes 
much clearer with a knowledge of the method of origin of the gill. 
MATERIALS 
Carpophores of Schizophyllum commune for this study were 
collected in the field and also grown on agar. Lima-bean agar, 
prune agar, and dung agar were favorable media. The cultures 
were grown in flasks of 50 c.c. and 250 c.c. capacity. Cultures 
were started from immature carpophores collected in the field, 
which were washed in distilled water before being transferred to 
the flask. | 
Within five days after the carpophores are planted оп it the 
agar surface is covered with a dense white growth of mycelia. 
The hyphae in cultures are conspicuously branched and micro- 
scopical examination shows numerous clamp connections. The 
hyphae average зи in diameter. 
Dense aggregations of buttons often develop over the agar 
surface. From the cut end of the carpophores and from their 
margins small buttons are first formed. А number of the buttons 
when they are in dense clusters fail to mature. Numerous ab- 
normal forms appear, as has been reported also by Miss Wakefield 
(09). In some cases an immature carpophore that is transferred 
to agar will continue its normal development by marginal growth 
and form a large normal fruit-body (PL. I, FIG. I). 
Various stages in the development of the carpophore were 
fixed for study in Flemming's medium mixture, dehydrated, and 
embedded in 52 paraffin. Sections were cut from би to I2u 
in thickness. 
THE YOUNG CARPOPHORE 
The young button appears as a dense, globular mass of inter- 
twined hyphae raised above the substratum. As noted, they 
often appear in clusters. These carpophore primordia later be- 
come differentiated into cylindrical outgrowths which enlarge 
