Download the full PDF (13Mb)

118 MICEOSCOPIC FUNGI.
extremity (rarely from tlie base) of the prismatic
spores. These tubes are straight or twisted,, simple
or forked^ and each of them becomes divided by
tranverse septa into four unequal cells towards their
apex, from each of which is produced a spicule
bearing a sporidium, or spherical secondary fruit,
in the same manESr as in the genera F'Uccinia and
Aregma. It should be observed, that the winter
spores of this rust are borne on the opposite surface
of the leaves to the summer spores
: for whilst
the latter are developed from the under surface, the
former are found on the upper.
This being also an
instance of di-morphism, the summer condition,
when spherical spores are produced, should not be
regarded as a distinct plant, and the name of
Lecythea caprearum does not merit retention in the
list of fungi. ;
There are five species of this interesting group,
or genus, found in Great Britain, to the residue of
which we may only briefly allude. It has already
been stated that, in summer, the yellow spores of a
rust are found on the under surface of birch-leaves.
These must be sought on the young twigs or
suckers, proceeding from the stumps of trees which
have been cut down :
pale discoloured spots on the
upper surface of the leaves indicate the presence of
the rust beneath. This is the Uredo hetulina of old
authors (begging their pardons, for some of them
still Hve), the Lecythea longicapsula of more recent
times, and the summersporesof ilfe?a???psor« hetulina^