6 ZECIDIOSPORES 
same time, shows that they mutually influence each other, and 
implies that all the cell-processes which go on are likewise 
under their common control. 
The upper cell, cut off from the fusion-cell, is the ezcidio- 
spore-mother-cell; the lower grows a little longer and then 
divides again in the same way, and thus a vertical series of 
eecidiospore-mother-cells is formed, the 
oldest at the top. Each of the zcidio- 
spore-mother-cells, as soon as produced, 
cuts off, by conjugate division, a small 
cell below, called the intercalary cell; 
this soon becomes disorganised and 
disappears, while the other portion 
becomes the aecidiospore. Thus the 
chain at first consists of alternations 
of «cidiospores and abortive spores, 
both containing two nuclei (Fig. 4); 
the function of the latter may be, 
by their disintegration, to enable the 
xcidiospores to separate more easily 
from one another, and thus to aid dis- 
persion by the wind. 
The peridiwm is composed of cells 
Fig. 4. P.Caricis. Chainof homologous with the spore-mother- 
young weidiospores, x 500. elis) They arise from basal cells con- 
a, fusion-tissue; b, basal rae — 
(fusion) cell, with con- taining two nuclei in exactly the same 
jugate nuclei; ¢, xcidio- . : 
spore-mother-cell; d, in. WAY; Occasionally even an intercalary 
tercalary cell; e, young ell is cut off, but it does not dis- 
zcidiospore. : : 
integrate. All of them thicken their 
walls and remain in close contact with one another; ultimately 
their contents disappear (Fig. 5). The central part of the 
dome-shaped peridium is composed of the terminal cells of 
the central spore-bearing hyphz ; they are probably less closely 
connected with one another, and the peridium ultimately 
bursts at that point. 
The spores, if placed in a damp atmosphere, germinate 
readily when mature and fresh. Only those spores which are 
at the top of the chains and can be shaken out easily by 
