GLERMINATION AND GROWTH. 143 
comes at its apcx a vital centre, and sprouts one or more linear 
buds, of which the elongation is occasionally intcrrupted by the 
formation of vesicular swellings. As Tulasne obscrves, the 
pseudospores of the Acidium and the greatcr number of Uredines 
are casily wetted wit water before arriving at maturity; but 
when they are ripe, on the contrary, they appear to be clothed 
with a greasy matter which protects them from tie liquid, 
forcing them almost all to rest on the surface. 
The pseudospores of Restelia are produced in strings or chap- 
lets, as in Acidium, with this difference, that instead of being 
contiguous they are separated by narrow isthmuscs. The ripe 
pseudospores are enveloped in athick 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 pseudosporcs, above all in those which 
have germinated, and have consequently become more trans- 
parent, 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 some- 
what similar, or at least not offering sufficient differences to 
warrant special reference in Uredo, Trichobasis, Lecythea, &c. 
In Cvleosporium there are two kinds of spores, one kind consist- 
ing of pulverulent single cells, and the other of elongated sep- 
tate cells, which break up into obovate joints. Soon after the 
roaturity 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 
