226 BOTANICAL GAZETTE [ocToper 
At this time a peculiar substance appears in the interstices of 
the ooplasm and fills the large vacuoles. It is not seen in younger 
stages, but is constant at this period and takes a rusty color when 
Flemming’s triple stain is used. When the substance first 
appears the tint is barely perceptible, but later it assumes a brick- 
red color. Slightly stained sections show a film in the vacuoles, 
often so curled up that an edge view is obtained, thus showing 
that the vacuoles actually contain a stainable substance. This 
substance is present in stages such as those represented in igs. 
ee YA 959 94- 
As the primitive wall reaches maturity it becomes covered 
by a layer of semi-transparent substance which is penetrated by 
straight pores. The condition is illustrated in fig. 92, where 4 
portion of this layer lies in such a position that both a surface 
and an edge view appear at one time. As the pores are close 
together and straight the structure reminds one of the hymenial 
surface of the Polyporei. Since the main substance of the layer 
is nearly invisible, the pores appear dark and look like papilla 
or cilia growing out of the primitive wall when seen in edge 
(fig. 92). A condition was noted by Wager in A. candids, and 
referred to as the “columnar condition,” which from the dese’ 
tions and drawings seems similar to this. There appc? eae : 
what later in this semi-transparent layer peculiar saucer-shaped 
masses of a dark substance of unknown nature (jig. 91): — 
are the first indication of the ridges so characteristic of 
mature epispore. There is but little periplasm at this 
y still undim" 
htly and show 
only a membrane and nucleolus. They frequently mass an 
in bunches, but there is no evidence that they 
furnish material for the exospore as is described for A. é 
To complete the endospore the saucer-shaped Bd 
ously mentioned (jig. gr), extend laterally and run es shows : 
forming the ridges. This gives the epispore the wee 
in fig. 93. Nuclei persist much longer outside of the “llowed 
but they seem to be functionless, and their history was not 
previr 
