the black receptacles on either surface of the leaf. These
may be regarded as the cardinal diseases of fungoid origin to which
useful plants are subject in this country.

Amongst those of less importance, but still troublesome enough to
secure the anathemas of cultivators, may be mentioned _Puccinia Apii_,
Ca., often successful in spoiling beds of celery by attacking the
leaves; _Cystopus candidus_, Lev., and _Glaeosporium concentricum_,
Grev., destructive to cabbages and other cruciferous plants;
_Trichobasis Fabae_, Lev., unsparing when once established on beans;
_Erysiphe Martii_, Lev., in some seasons a great nuisance to the crop
of peas.

Fruit trees do not wholly escape, for _Roestelia cancellata_, Tul.,
attacks the leaves of the pear. _Puccinia prunorum_ affects the leaves
of almost all the varieties of plum. Blisters caused by _Ascomyces
deformans_, B., contort the leaves of peaches, as _Ascomyces
bullatus_, B., does those of the pear, and _Ascomyces juglandis_, B.,
those of the walnut. Happily we do not at present suffer from
_Ascomyces pruni_, Fchl., which, on the Continent, attacks young
plum-fruits, causing them to shrivel and fall. During the past year
pear-blossoms have suffered from what seems to be a form of
_Helminthosporium pyrorum_, and the branches are sometimes infected
with _Capnodium elongatum_; but orchards in the United States have a
worse foe in the "black knot,"[f] which causes gouty swellings in the
branches, and is caused by the _Sphaeria morbosa_ of Schweinitz.

Cotton plants in India[g] were described by Dr. Shortt as subject to
the attacks of a kind of mildew, which from the description appeared
to be a species of _Erysiphe_, but on receiving specimens from India
for examination, we found it to be one of those diseased conditions of
tissue formerly classed with fungi under the name of _Erineum_; and a
species of Torula attacks cotton pods after they are ripe. Tea leaves
in plantations in Cachar have been said to suffer from some sort of
blight, but in all that we have seen insects appear to be the
depredators, although on the decaying leaves _Hendersonia theicola_,
Cooke, establishes itself.[h] The coffee plantations of Ceylon suffer
from the depredations of _Hemiliea vastatrix_, as well as from
insects.[i] Other useful plants have also their enemies in parasitic
fungi.

Olive-trees in the south of Europe suffer from the attacks of a
species of _Antennaria_, as do also orange and le