8PHaERIACE2E IMPERFECTAE COGNITA. 
87 
4423. Metasphaeria obtusata ( Schw .). Sphaeria obtusata, Schw. 
Amer. Bor. 1737. 
Asci clavate, stipitate ; sporidia lanceolate, 5-7 septate, 50 x 7 /x 
hyaline. 
4426. Macrophoma meloplaca (Schw.). Sphaeria meloplaca, Schw. 
Amer. Bor. 1753. 
Sporules elliptical, hyaline, 20 x 10 /*. 
4433. Phomatispora echinophila (Schw.). Sphaeria echinophila, 
Schw. Amer. Bor. 1755. 
Asci cylindrical, sporidia nniseriate, narrowly elliptical, hyaline, 
6x2 fi. 
BACTERIA IN PLANT DISEASE. 
For some time it has been suspected that microbes have some- 
thing to do with certain obscure diseases of plants. These sus- 
picions seem to be developing themselves almost into certainties, 
and to present another curious analogy between the diseases of 
animals and plants. The disease known in the United States as 
“ Peach yellows ” has constantly evaded all search for mycelium, 
or trace of fungoid development, and yet it is a destructive and 
insidious foe. Professor Burrill made investigations in 1888 and 
1889, but without any decided results. Nevertheless he reports 
that “ he had found in the tissues of the root and of the old and 
young stems of diseased trees an organism classed with the 
bacteria, which is not known to occur elsewhere. This organism 
has been frequently obtained by methods of culture under circum- 
stances which preclude the possibility of its coming from anything 
except the inner cells of the tree. He had it growing in artificial 
media, and it exhibited all the peculiarities of a pathogenic rather 
than a saprophytic microbe. It had peculiarities which served to 
distinguish it from all others of its kind, and he was convinced it 
had never before been described by anyone. He found it in 
every set of specimens examined known to be affected with this 
disease, and had thoroughly tried in the same manner to find it in 
healthy stock and failed.” Still further he says, “ If the disease 
is really due to the microbe mentioned the malady differs widely 
from that of any heretofore described bacterial injury to living 
vegetation. The microbe must be sparsely, but widely, distributed 
through the still living tissues of the tree, in which it must very 
slowly develop without causing evident local disturbance. This 
latter especially is entirely at variance with known effects of para- 
sitic organisms. But we know that the peach tree affected with 
this disease very gradually succumbs, lingering along several 
years without local injury of pronounced type.”* 
On the subject of the California vine disease, Mr. Pierce, a 
special agent sent to investigate the disease, states that yellow 
* Report of the Secretary of Agriculture, U.S., Section of Vegetable 
Pathology for 1889, p. 423. 
