332 BOTANICAL GAZETTE [NOVEMBER 
being verrucose from the presence of numerous brownish or yellowish- 
brown points; but when one examines the wall at the middle focal 
plane, these colored dots are seen not to project beyond the outer 
surface of the wall, though both above and below the middle focal 
plane they do appear as echinulations. The structure seemed to be 
so puzzling that I was led to employ the oil immersion lens (Zeiss 
apochromatic homogeneous immersion lens, equivalent focus 1.5" 
and compensation ocular 6). This revealed the true structure of 
the spore wall. It is hyaline or nearly so, and is perforated with 
numerous slender rodlike extensions of a brown or yellowish-brown 
substance, which appear as if they might be projections of the colored 
content of the spore. These do not extend beyond the outer surface 
of the wall, and they radiate from the endospore through the hyaline 
wall, They are especially prominent at the smaller end of the oval 
spore where the hyaline wall is considerably thicker, sometimes 
forming a broad conelike cap to the spore. 
In order to demonstrate this peculiar structure beyond doubt, 
photomicrographs were made of four different species and forms, 
and these are reproduced in pl. 19. The spores which were lying 
so that the middle plane was in focus show very clearly that the wall 
is smooth, and that it is perforated with these short, dark-colored, 
rodlike extensions. These are very evident all around the spore, 
but are remarkably prominent at the apex, especially in those spores 
where the broad conelike hyaline cap is still intact. Where the 
middle plane of the spore is not in the focal plane, the spores appear 
“warty,” but this is only an optical illusion. This is especially 
striking in fl. fig. 6, where the middle plane of nearly all the po 
was out of focus. For the species from which these photomicro- 
graphs were made the reader is referred to the description of figures. 
The fact that the spore wall is hyaline or subhyaline, and perforated 
with dark lines, gives such prominence to the latter that they - 
apt to be taken for warts or echinulations when the examination 
hasty. The hyaline portion of the spore wall appears also to be 
of a less firm consistency than the colored perforations or lines, and 
if the spores dry at a certain age, perhaps before they are quite ma 
ture, the hyaline portion of the wall appears often to shrink or colla 
somewhat, thus making the colored points stand out as echinulations, 
