W.G. Farlow— Disease of Olive and Orange Trees. 45 
exceedingly like a collection of oil-globules, or very small eggs. 
e do not pretend to say that what Tulasne saw was nota 
membrane of vegetable substance,—a part of the fungus itself ; 
but, in the Californian specimens, we had something which 
looked very much like the mm. of Tulasne’s figure, and, in this 
case, we have satisfied ourselves, by observation and experiment, 
that it is of animal nature, and not a part of the fungus, which, 
instead, was growing upon it. It is a little difficult to under- 
stand, from what is already known of the developement of fungi, 
ow any fungus could begin as a very thin membrane, compos 
of small cells filled with oil. The initial stage of fungi, if we 
except the Myxomycetes, as far as we know, is filamentous, not 
membranous. 
The result of our examination of the diseased orange and olive 
leaves is briefly as follows: The disease, although first attract- 
ing the eye by the presence of a black fungus, is not caused b 
it, but rather by the attack of some insect, which itself deposits 
some gummy substance on the leaves and bark, or so wounds 
the tree as to cause some sticky exudation, on which the fungus 
especially thrives. It.is not denied that the growth of the fun- 
gus greatly aggravates the trouble already existing, by so encas- 
ing the leaves as to prevent the action of the sunlight; we only 
say, that, in seeking a remedy, we are to look further back than 
the fungus itself,—to the insect, or whatever it may be, which 
has made the luxuriant growth of the fungus ible. With 
regard to the fungus, we are able to assert that it is the same on 
both olives and oranges,—the species described by Berkeley and 
aziéres under the name of Capnodium Citri, which seems 
to us, together with the pycnidial state described by Montagne 
under the name of Antennaria elwophila, to be but two states of 
& species identical with that described by Tulasne as Fumago 
salcina. It remains yet to find tbe asci on olives or oranges 
which will probably be accomplished without difficulty in Cali- 
fornia. The earliest stages of the fungus should be studied by 
Some one living near orange groves; for, although the disease 
been known to attack greenhouse plants, it is not very com- 
mon, or, in that case, so favorable for study. specially is it to 
be desired that careful notes of the extent and manner of se 
ance of the disease, and the climatic and hygrometric conditions 
attending it, should be carefully recorded. : 
As a remedy, alkaline soaps, as strong as the trees will bear, 
Will no doubt prove advantageous in ease of the oranges; but, 
in the case of the olives, much less good is to be ex 
Owing to the nce of the stellate hairs on leaves and twi 
ith this, our notice of the disease from a botanical stand-point 
ends; and we commend the subject to the attention of entomo- 
logists, 
