cilia show themselves (_d_), and by means of these appendages the
entire globule moves in an oscillating manner as one by one the
zoospores disengage themselves, each becoming isolated and swimming
freely in the surrounding fluid. The movement is precisely that of the
zoospores of Algae.

[Illustration: FIG. 92.--Resting spore of _Cystopus candidus_ with
zoospores escaped.]

The generation of the zoospores commences within from an hour and a
half to three hours after the sowing of the conidia on water. From the
oogonia, or resting spores, similar zoospores, but in greater number,
are generated in the same manner, and their conduct after becoming
free is identical. Their movements in the water usually last from two
to three hours, then they abate, the cilia disappear, and the spore
becomes immovable, takes a globose form, and covers itself with a
membrane of cellulose. Afterwards the spore emits, from any point
whatever of its surface, a thin, straight or flexuous tube, which
attains a length of from two to ten times the diameter of the spore.
The extremity becomes clavate or swollen, after the manner of a
vesicle, which receives by degrees the whole of the protoplasm.

De Bary then proceeds to describe experiments which he had performed
by watering growing plants with these zoospores, the result being that
the germinating tubes did not penetrate the epidermis, but entered by
the stomates, and there put forth an abundant mycelium which traversed
the intercellular passages. Altogether the germination of these
conidia or zoospores offers so many differences from the ordinary
germination of the Uredines, and is so like that which prevails in
_Peronospora_, in addition to the fact of both genera producing winter
spores or oogonia, that we cannot feel surprised that the learned
mycologist who made these observations should claim for _Cystopus_ an
affinity with _Peronospora_ rather than with the plants so long
associated with it amongst the _Coniomycetes_.

In passing from these to the _Mucedines_, therefore, we cannot do so
more naturally than by means of that genus of white moulds to which we
have just alluded. The erect branched threads bear at the tip of their
branchlets spores, or conidia, which conduct themselves in a like
manner to the organs so named in _Cystopus_, and oogonia or resting
spores developed on the mycelium within the tissues of the foster
plant also give origin to similar zoospores.

The conidia are