n a thick tegument, of a dark brown
colour. They germinate readily on water, producing a filament fifteen
times as long as the diameter of the spore. This filament is sometimes
rolled or curved. Towards its extremity it exhibits protuberances
which resemble the rudiments of ramuli, or they terminate in a vesicle
which gives rise to a slender filament. The tegument of these
pseudospores, above all in those which have germinated, and have
consequently become more transparent, it is easy to see has many
pores, or round ostioles.

In _Peridermium_ the pseudospores, when dropped upon water, germinate
at any point of their surface. Sometimes two unequal filaments issue
from the same spore. After forty-eight hours of vegetation in the air,
the greater part had already emitted a multitude of thick little
branches, themselves either simple or branched, giving to the
filaments a peculiar aspect. Tulasne did not on any occasion observe
the formation of secondary spores.

In the Uredines proper the germination seems to be somewhat similar,
or at least not offering sufficient differences to warrant special
reference in _Uredo_, _Trichobasis_, _Lecythea_, &c. In _Coleosporium_
there are two kinds of spores, one kind consisting of pulverulent
single cells, and the other of elongated septate cells, which break up
into obovate joints. Soon after the maturity of the pulverulent
spores, each begins to emit a long tube, which is habitually simple,
and produces at its summit a reproductive cellule, or reniform
sporule. The orange protoplasm passes along the colourless tubes to
the terminal sporule at the end of its vegetation. The two forms of
spores in this genus are constantly found on the same leaf, and in the
same pulvinule, but generally the pulverulent spores abound at the
commencement of the summer. The reniform sporules begin to germinate
in a great number as soon as they are free; some few extend a filament
which remains simple and uniform, but more commonly it forms at its
extremity a second sporule. If this does not become isolated, to play
an independent life, the filament is continued, and new vesicles are
repeated many times.

[Illustration: FIG. 82.--Germinating pseudospores of (_b_) _Coleosporium
Sonchi_; (_s s_) secondary spores, or sporules (Tulasne).]

[Illustration: FIG. 83.--Germinating pseudospore (_b_) of _Melampsora
betulina_ (Tulasne).]

In _Melampsora_ the summer spores are of the _Lecythea_ type, and were
i