Leleutospores. 43 
vera, poarum). In either case the germinative process is 
the same; This consists in the protrusion of a germ-tube 
from the teleutospore through the germ-pore above men- 
tioned, which tube is really an extension of the endospore 
through the germ-pore. This tube consists of a hyaline, 
homogeneous membrane, into which the protoplasm con- 
tained within the spore passes. This tube (the promy- 
celium) does not, like the germ-tubes of the uredospores 
and ecidiospores, elongate indefinitely, but, after attaining 
a certain length, ceases to grow onwards and terminates in 
a blind, blunt extremity. Into the promycelial tube the 
protoplasm passes from the spore, and accumulates towards 
the peripheral extremity, so that the end nearest the spore 
becomes empty. The distal end now exhibits one or more 
septa, which are formed from above downwards. At the 
same time, from each compartment thus divided off there 
arises a single, short, pointed branch ; these at their points 
dilate. The dilated end becomes the receptacle for the 
protoplasm originally contained in each compartment, and 
rapidly assumes an oval or subreniform outline (the pro- 
mycelial spore), which in the course of a few hours becomes 
abstricted and falls off (Plate IV. Figs. 2-10). The pro- 
mycelial spores, when placed in water or upon any damp 
surface, forthwith germinate (Plate III. Fig. 24). This 
process consists in the outgrowth, from some point of their 
surface, of a short but acutely pointed tube. Placed upon 
the cuticle of a living leaf of the proper host-plant, this 
germ-tube turns its point downwards, and, piercing the 
epidermal cell-walls, enters the tissue of the leaf (Plate IV. 
Fig. 1). Having thus gained an entry into its host, the 
protoplasm contained in the promycelial spore passes down- 
wards into the germ-tube, leaving the spore empty. The 
empty spore-cell falls off, and the minute opening through 
which the germ-tube has entered the epidermal cell ceases 
