GERMINATION AND GROWTH. 153 
spora rather than with the plants so long associated with it 
amongst the Coniomycetes. 
In passing from these to the JLucedines, 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 Cys/opus, and oogonia or resting spores developed on 
the mycelium within the tissues of the fuster plant also give 
origin to similar zoospores. 
The conidia are borne upon erect, elongated filaments, origi- 
nating from the creeping mycelium. These threads are hollow, 
and rarely septate; the upper portion divided into numerous 
branches, and these again are subdivided, the ultimate ramuli 
each terminated by a single conidium. .This body when mature 
is oval or elliptical, filled with protoplasm, but there is a diver- 
sity in their mode of germination. In the greater part, of 
which P. effusa may be taken as an example, the conidia have 
the function of simple spores. Placed in favourable conditions, 
each of them puts forth a germ-tube, the formation of which 
does not differ in any essential point from what is known of the 
spores of the greater part of fungi. 
The short oval conidia of P. gangliformis have little obtuse 
papille at their apex, and it is at this point that germination 
commences. 
The conidia of P. densa are similar, but the germination is 
different. When placed in a drop of water, under favourable 
circumstances, the following changes may be observed in from 
four to six hours. The protoplasm, at first uniformly distributed 
in all the conidia, appears strewn with semi-lenticular, and nearly 
equidistant vacuoles, of which the plane face is immediately in 
contact with the periphery of the protoplasm. These vacuoles 
number from sixteen to eighteen in P. macrocarpa, but are less 
numerous in P. densa, A short time after the appearance of the 
vacuoles the entire conidium extends itself so that the papilla 
disappears, Suddenly it reappears, elongates itself, its attcnu- 
ated membrane vanishes, and the protoplasm is expelled by 
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