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now least suspected. No one was prepared to expect zoospores 
in the conidia of white rusts (Gysto]pus\ or in the oospores of 
the parasitic moulds {Peronospora) until De Bary’s investiga- 
tions set the matter at rest. Such a complex method prevails 
in some fungi, as in Bunt {Tilletia caries) an alternation of 
generations, that we may even suppose that it is not more 
simple in agarics. Curious instances of conjugation have also 
been discovered, as by De Bary^' and Tulasne,f bringing the 
mode of development more into harmony with what has been 
observed in the lower alga3. Something analogous to this is 
detailed by Professor Karsten,:}: as having been observed by him 
to take place on the mycelium of the common mushroom and 
Acjaricus vac/inatus. He says, “ In Agaricus cccmpestris, by 
gradually going back from the forms recognisable with cer- 
tainty as the youngest states of the cap to smaller ones, I found 
an organ which, from its peculiar form and texture, I could not 
but regard as the first commencement of the fruit. This was 
an oval, almost egg-shaped, simple cell, standing upon a short 
peduncle of the thickness of the mycelium, and of from three 
to four times the diameter ^ of this, filled with albuminous 
matter and overgrown by filaments of the mycelium, which 
w'ere at first single, but by continually increasing in number, at 
last form a thick rind {peridium, velum) over the central 
ovicell, which, in the meantime, increases in size.” In Agaricus 
vaginatus he found similar bodies (fig. 12), and beside them 
cylindrical cells springing from the mycelium. In one instance 
this cylindrical filament consisted of two cells, the upper of 
which contained a turbid fluid. This upper portion was in 
contact with the oval cell, so that it seemed to be pressed into 
the latter, and amalgamated with it at the point of contact 
(fig. 11). Karsten names these stalked ovoid cells archegonia, 
and concludes that the conjugation of these two bodies, the cylin- 
drical with the ovoid, is a fecundative process, similar to what he 
had described as taking place in a lichen {Coenogonium). At 
present these observations have not been confirmed, and it would 
]je idle to speculate upon their value, or to accept them as 
an elucidation of the m}^stery of germination. If we admit 
Karsten’s theory, it has still to be shown w^hat are the condi- 
tions under which these two forms of cells are produced. The 
germination of the spore and growth of mycelium is the 
• “ Annalefl des ScionCG.s naturelles.” Surio V: Botaniqiio. Vol. v. p. 343, 
ann. Morphologio und Physiologie der Pilze etc.” Leipsic, 1806, 
t Note sur lea Pheiiomfenea de Copulation que pr^sentent quelquea cham- 
pignona. Ann. dea Sc. nat.” S^rieV: Botanique. Vol. v. p. 211. ISGO. 
t “ BotaniacheL'ntersuchungen,” 1860, pp. 100-109. Trnnalatedin ^^Ann, 
and Mag. of Natural History,” Series iii. vol. xix. p. 73. 1807. 
