ss partition. The
delicate wall of these parts shrinks up until it is unrecognizable;
all the conidia of the panicle approach one another to form an
irregular grape-like bunch, which rests loosely on the bearer, and
from which it easily falls away as dust. If they be brought into water
they fall off immediately; only the empty, shrivelled, delicate skins
are to be found on the branch which bore them, and the places on which
they are fixed to the principal stem clearly appear as round
circumscribed hilums, generally rather arched towards the exterior.
The development of the main stem is not ended here. It remains solid
and filled with protoplasm as far as the portion which forms the end
through its conidia. Its end, which is to be found among these pieces,
becomes pointed after the ripening of the first panicle, pushes the
end of the shrivelled member on one side, and grows to the same length
as the height of one or two panicles, and then remains still, to form
a second panicle similar to the first. This is later equally
perfoliated as the first, then a third follows, and thus a large
number of panicles are produced after and over one another on the same
stem. In perfect specimens, every perfoliated panicle hangs loosely to
its original place on the surface of the stem, until by shaking or the
access of water to it, it falls immediately into the single conidia,
or the remains of branches, and the already-mentioned oval hilums are
left behind. Naturally, the stem becomes longer by every perfoliation;
in luxuriant specimens the length can reach that of some lines. Its
partition is already, by the ripening of the first panicle from the
beginning of its foundation, strong and brown; it is only colourless
at the end which is extending, and in all new formations. During all
these changes the filament remains either unbranched, except as
regards the transient panicles, or it sends out here and there, at the
perfoliated spots, especially from the lower ones, one or two strong
branches, standing opposite one another and resembling the principal
stem.

[Illustration: FIG. 28.--_Polyactis cinerea._ _a._ Apex of hypha.]

The mycelium, which grows so exuberantly in the leaf, often brings
forth many other productions, which are called _sclerotia_, and are,
according to their nature, a thick bulbous tissue of mycelium
filaments. Their formation begins with the profuse ramification of the
mycelium threads in some place or other; gener