Teleutospores. 39 
In the American species P. amorphe, Curtis, the mother- 
cell remains distinct from the spore-wall of the teleutospore, 
separated by a gelatinous substance. When the teleuto- 
spores of this species are placed in water the mother-cell 
swells in a very remarkable manner, and can be seen 
surrounding the teleutospore (Plate IV. Figs, 15, 16, 17). 
The germinal canal penetrates the membrane only, being 
closed below by the endospore. The germinal canal 
of the lower spore,is placed laterally immediately below 
the septum. In most species the exterior of the spore is 
smooth, but in several it is tuberculate, papillose, or verru- 
cose. In one of the American species, P. aculeata, these 
protuberances are nearly cylindrical and curved. In P. 
fusca, pruni, etc., the tubercles are small, but exceedingly 
numerous, covering the whole exterior of the spore. In 
P. smyrnii they are few, discrete, and conical. P. coronata 
is characterized by a crown of elongated, variously bent, 
cylindrical processes, surmounting the upper segment. 
Here the superior germ canal is not situated at the apex 
of the spore, but towards one side (Plate IV. Fig. 3), just 
as it normally occurs in the lower cell of other species. 
The general outline of the Puccinia spore varies not only 
in different species, but also in individual spores from the 
same spore-bed. In P. prunz and fusca the teleutospores 
consist of two distinct superimposed globose bodies, 
flattened at the point of contact; these easily separate 
from one another by rough manipulation. Not infre- 
quently, only one segment of the spore becomes de- 
veloped, the other, usually the lower, remaining abortive. 
In some instances numerous single spores (mesospores) 
are produced, either mixed with the normal bicellular 
spores or without them, as in P. obscura, scirpi, convolvulz, 
porri, and sonchi. These mesospores are morphologically 
analogous to the teleutospores of Uromyces. P.rudbigo-vera, 
