524 Fischer . — The Biology of A r miliaria mucida, Schrader. 
Usually these arise in clusters of a large number of individuals crowded 
together. In twenty-four hours, in vigorous growths, a small cap is already 
differentiated, the protuberances having elongated appreciably (Fig. 18). 
The increase in size and bulk goes on rapidly, and in three or four days the 
cap presents a very definite and separate structure ; the veil is already 
stretched out and transparent, allowing the gills to be seen through it 
(Figs. 19 to 22). In another two or three days the veil has separated 
off altogether from the edge of the pileus, which then begins to expand, 
first to a horizontal position, and finally its edges curl up so that the 
lamellae are exposed laterally (PI. XXXVIII, Figs. 23 and 24). In another 
paper I have described the anatomical development of the fruit body (8). 
Owing to want of space in these cultures and the consequent approxi- 
mation of several fruit bodies, compound carpophores are liable to be 
formed in which three or four distinct ones agglomerate into a single stipe 
and pileus, the lines of union remaining recognizable. 
In this crowded condition some of the sporophores may grow down- 
wards (Fig. 19), though they never do so when space allows. 
In one case the fruit bodies appeared as rounded instead of conical 
protuberances, and eventually had bulbous bases to their stipes (Fig. 25). 
The average size of the artificially produced fruit bodies was con- 
siderably smaller than those found in nature ; in no case did the expanded 
pileus exceed two inches in diameter. The stipes, too, are rather more 
slender and elongated. As they were mostly grown in the dark, this was 
only to be expected. In this connexion a curious feature presented itself. 
All cultures grown in the dark produced pure white carpophores, which is 
the prevalent colouring in nature, whereas those grown in the light were 
invariably dark brown or, at least, a decided fuscous grey, turning somewhat 
lighter with maturity. Moreover, if when still young the culture was trans- 
ferred from the light to the dark, or vice versa, the hue changed to that 
appropriate to the altered conditions. If the transfer was effected at a late, 
stage, however, no appreciable change in tint was observable. 
These facts may perhaps be taken to throw some light on the differ- 
ences in colour noticed by the several authors in the naturally grown 
fructifications. 
The fructifications reached maturity equally well when grov/n in 
the dark or in the light, but, on the whole, they were a little less robust , 
when kept entirely in the dark and matured a little less rapidly. 
There remains but one more culture to be given special notice. In 
a bulb flask a bread culture was made in the usual way, but was moistened 
with a 10 per cent, watery solution of glucose and a small quantity of 
4 per cent, lactic acid. This was inoculated with a small piece of bread 
permeated with mycelium, taken from one of the cultures that eleven days 
later began to fructify. The inoculation was effected on. January 18, and. 
