ee British Uredinee and Ustilaginee. 
spores in the spore-bed. Whether this be the simple 
passive process we have hitherto regarded it or not is 
undetermined. It is quite possible that it may be aided by 
a projective force, as Brefeld * has shown in the Agaricini. 
In them the basidia become by degrees fuller of protoplasm, 
until a certain state in the tension of the elastic walls takes 
place. When this has attained its full extent, the upper 
part of the basidium, immediately below the spore, gives 
way and becomes split off all round, the spore being 
projected from its sterigma at the point of its attach- 
ment. A similar process occurs in. Pilobolus, only in this. 
case the rupture is lower down, and not at the exact point 
of junction of the spore with its basidium. 
As soon as each uredospore is ripe it is capable of germi- 
nating, and when placed in a sufficiently damp environment 
it does so in a few hours. This process is accomplished in 
the same manner as has been already described under the 
zecidiospores. It consists in the protrusion of a germ-tube 
through one or more of the germ-pores, which branches, 
elongates, circumnutates, and receives the protoplasm from: 
the interior of the spore, and passes it onwards to its peri- 
pheral extremity (Plate III. Figs. 11, 12, 13). In the 
same way its extremity, or the extremity of one of its 
branches, enters into one of the stomata of the host-plant, 
and in its tissues develops a fresh mycelium (Plate III. 
Fig. 15). 
Under certain circumstances, when the germ-tube 
cannot enter a stoma, instead of growing in the mode 
described, it dilates in a bulbous manner f at its extremity 
into a spherical dilatation, into which the orange granules 
accumulate ; or it may give off one or more lateral out- 
* Brefeld, ‘‘ Schimmelpilze.” 
+ Plowright, ‘‘Germination of Uredines;” ‘‘Grevillea,” vol. ix. pl. 
‘159, figs. 10, 11, 12. 
