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expelled through the swelling above-mentioned, which has become 
pierced by a small passage, and soon swim off by the aid of ciliz ; 
they then fix themselves upon one of the stomata of the leaf into 
which they project a thread or tube, and so produce a mycelium 
in the intercellular passages similar to that from which they 
originated. Besides these conidia, De Bary found large spherical 
bodies with a thick membranous coat produced upon the threads 
of the mycelium within the leaf, whose presence was indicated by 
a red or orange colour visible on the surface ; these were the 
result of a process of fertilization similar to that of certain Alge, 
as Saprolegnia, and in Peronospora among Fungi. Pringsheim 
named them gonospheres; De Bary calls them oospores, after 
fertilization. The oospore retains its form for some months, and 
is at length set free by the decomposition of the surrounding 
tissues. The endospore (or body contained within the oospore) 
then bursts forth and is found to be full of zoospores similar to 
those produced from each of the conidia. De Bary considered 
that each oospore contains one hundred or more of these zoospores. 
They germinate, like the other zoospores, upon the stomata. It 
was observed that the threads penetrated the leaves only at a 
stomate, and also that the threads soon ceased to grow unless they 
fell on a cotyledonal stomate ; on the stomata of true leaves they 
emitted threads, but these threads soon ceased to grow. I must 
now pass on to other Genera. Ustilago consists of unicellular 
spores produced on delicate threads; it occupies sometimes the 
fruit of Carices and other plants, and even the anthers of some, as 
Silene dioica. Miss Becker observed that in this case it produced 
a change of sex in the plant by a process of repression or 
degradation, converting the male flowers into female, or rendering 
the plants hermaphrodite. 
The 16th Order, Atcideacei is characterized by a cellular 
peridium. The Mycelium traverses the tissue of living plants 
which are terminated by single, or concatenate, spores. These 
