ON THE PILOBOLHXE. 
217 
which attracts attention by its golden colour, and so the 
aspect of a group of the plants is perceptibly different, 
according as the reservoir is visible or not. While exceptions 
of course occur, it will yet be found that its position is pretty 
constant for each species, and one of the British species is 
recognisable by the naked eye, on account of the brilliant 
yellow colour which it presents, owing to its basal reservoirs 
being mostly above the matrix. The reservoir is not always 
terminal, as it is usually in P. Kleinii; in the species identified 
with Bolton’s Mucor roridus, the P. roridus of Persoon, and 
P. microsporus of Klein, both the latter author and Van 
Tieghem found the reservoir most often intercalary—that is, 
placed in the course of the mycelium, with a mycelian 
apophysis on each side. In Van Tiegliem’s P. nanus there 
were found two, three, or even five such placed contiguously. 
It sometimes occurs so also in P. crystallinus. 
j .— Dehiscence of the Sporange. 
We will now proceed to consider more closely the ultimate 
fate and projection of the sporange. In the first place, let 
me say that the earlier observers completely misunderstood 
the mechanism by which this is effected. There are really 
two phenomena to be studied, the dehiscence of the sporange 
and its projection. I have described how the upper portion 
of the wall of the sporangium becomes black and cuticularised; 
this thickening process stops rather abruptly along a circular 
line a little below the equator of the sporange, so that the 
“ cap” extends over a little more than a hemisphere. The 
narrow zone lying between this circle and the circle of 
insertion of the columella not only is not thickened, but 
becomes thinner and more fragile, and at last possesses in a 
conspicuous degree that property, characteristic of the 
membrane of many Mucorine sporangia, of breaking up into 
minute particles on the application of water, to which the 
name of diffiuence is given. The hyaline interstitial substance, 
in which the spores are embedded, extends beyond the spore- 
mass, so as to occupy a portion of the interval between it and 
the wall of the sporangium. It does not, however, in the 
normal state, quite come into contact with the wall, at any 
rate in the lower portion, where moreover this peripheral 
layer is thicker than it is beneath the “ cap” (Fig. 8). When 
the sporange is mature, the application of a drop of water to 
the diffluent zone causes it immediately to disappear, the 
edges of the black cap curl up a little, and the gelatinous 
substance greedily imbibes the water, and swells up more or 
