confluens and the Morphology of the Ascocarp . 337 
hours. The fruits are densely packed in small tufts, and are 
a delicate pinkish or salmon colour when growing among 
leaves. The mycelium and sexual organs are glistening 
white, and resemble a delicate frost-like tracery on the 
blackish substratum. The best material is always found 
under and among the leaves, so as to be at least partially 
protected from the brightest light in the cases I have observed, 
though it is described as growing directly on the ground on 
burned places in Europe. My material was collected in May 
and June of 1898 at Lake Forest, and I was able to obtain 
unlimited quantities of it at that time, sufficient for experi¬ 
menting with all varieties of fixing-fluids, &c. 
As just noted, the material for my investigations was found 
growing on charred or decayed leaves or leaf mould. Bits 
of this substratum a few mm. in diameter and richly covered 
with fruiting bodies, young or old as might be desired, were 
fixed in toto , embedded in paraffin and sectioned for the 
most part in a plane vertical to the surface of the substratum 
as it lay when collected. In this way the sexual apparatus 
was fixed without distortion, as would hardly have been 
possible had the attempt been made to handle the rosettes 
of oogonia and antheridia separately. The growth of the 
mycelium is peripheral, from a centre outward, and the bits 
of the substratum usually contained fruits of varying ages, 
the youngest lying near the border of a mycelial growth with 
progressively older stages toward the centre. The develop¬ 
ment is, however, so rapid that it is not possible to find the 
fully mature as well as the youngest stages on any single 
mycelium. The oldest fruits found on mycelia, at whose 
edges the rosettes were first appearing, showed only a few 
partly ripened asci, and conversely those mycelia which showed 
fully mature pink apothecia at their centres rarely bore fruits 
as young as the fertilization-stages at their margins. By 
noting such points as this one is enabled to be sure of 
obtaining an abundance of material at all stages of develop¬ 
ment. The substratum on which I have found the Pyronema 
most abundant, makes it especially favourable for sectioning, 
A a 
