aware that
these results have been confirmed, or that the sowing of the spores of
_Roestelia_ on juniper resulted in _Podisoma_. Such experiments should
be received always with care, and not too hastily accepted in their
apparent results as proven facts. Who shall say that _Roestelia_ would
not have appeared on _Sorbus_ within two months without the sowing of
_Podisoma_ spores?--because it is not by any means uncommon for that
fungus to appear upon that plant. It is true many mycologists write
and speak of _Roestelia_ and _Podisoma_ (or _Gymnosporangium_) as
identical; but, as we think, without the evidence being so complete as
to be beyond suspicion. It is, nevertheless, a curious fact that in
Europe the number of species of _Roestelia_ and _Podisoma_ are equal,
if one species be excluded, which is certainly not a good _Podisoma_,
for the reception of which a new genus has been proposed.[e]

Amongst the ascigerous fungi will be found a curious but interesting
genus formerly called _Cordyceps_, but for which Tulasne, in
consequence of the discovery of secondary forms of fruit, has
substituted that of _Torrubia_.[f] These curious fungi partake more
or less of a clavate form, and are parasitic on insects. The pupae
of moths are sometimes seen bearing upon them the white branched
mould, something like a _Clavaria_ in appearance, to which the name of
_Isaria farinosa_ has been given. According to Tulasne, this is the
conidia form of the bright scarlet, club-shaped body which is also
found on dead pupae, called _Torrubia militaris_. An American mould of
the same genus, _Isaria sphingum_, found on mature moths,[g] is in
like manner declared to be the conidia of _Torrubia sphingum_;
whereas a similar mould, found on dead spiders, called _Isaria
arachnophila_,[h] is probably of a similar nature. An allied kind
of compact mould, which is parasitic on _Cocci_, on the bark of
trees, recently found in England by Mr. C. E. Broome, and named
_Microcera coccophila_,[i] is said by Tulasne to be a condition of
_Sphaerostilbe_, and it is intimated that other productions of a
similar character bear like relations to other sphaeriaceous fungi.
For many species of _Torrubia_ no corresponding conidia are yet
known.

Some instances might be noted, not without interest, in which the
facts of dimorphism or polymorphism have not been satisfactorily
proved, but final judgment is held in suspense until suspicion is
replaced by conviction. Some