364 REPORT OF THE COMMISSIONER OF AGRICULTURE. 
owing to the brown hyphe among the spores. It is from them that 
the spore masses already spoken of project. They occur only over 
the ight center of the spot, the black line forming their limit; in fact, 
the light color is probably caused by the spores and ruptured epi- 
dermis. 
The presence of the largé dark-colored hyphe raises a question of 
classification. These hyphz are not mentioned in any description 
of Gleosporium, and, so far as is known, are not present in any other 
species of that genus, but are, on the contrary, characteristic of the 
genera Vermicularia and Colletotrichium. The appearance and 
structure of the bean fungus accords perfectly with the description 
of Colletotrichiwm, even to the location of the brown hyphe (sete) 
about the circumference of the pustule, and if the setge are an organic 
part of the bean fungus it seems probable that the name must be 
changed from Gleosporium to Colletotrichium.* 
(e) TREATMENT, 
So far as possible plant in a dry and airy situation in light soil. 
Sulphur has been used and is reported to check the disease somewhat, 
but is not a sure protection. Undersome circumstances applications 
may be made of solutions of sulphate of iron or copper, but the use 
of these compounds on this fruit can not be generally recommended 
owing to their poisonous character. Experiments might be made 
with liver of sulphur, 1 ounce to d gallons of water. The action of 
ae poe is immediate, and it may be freely used without danger 
to health. 
9,—LEAF-SPOT DISEASE OF CATALPA. 
(Plate VIL.) 
(a) GENERAL OBSERVATIONS. 
The foliage of a number of our ornamental shade trees is some- 
times seriously disfigured or caused to fall prematurely by the at- 
tacks of parasitic fungi. A notable example of this is the case of the 
catalpa (C. bignonioides), some trees of which, growing on grounds 
near the Department buildings, have had their leaves more or less 
injured from this cause for several seasons past. The work of the 
fungus is manifest by round, brown spots upon the leaves which ap- 
pear early in June, and in some few instances the ravages of the 
parasite have been so severe as to nearly defoliate certain trees by the 
end of July or early in August. 
The geographical limits of the disease are not known, but it is evi- 
dently quite extended, as samples of the affected leaves have been 
observed in widely separated localities. 
(6) EXTERNAL CHARACTERS. 
So far as we know the attacks of the the parasite are confined to 
the leaves, where it produces the brown spots mentioned above. 
These spots are round, varying from 3™™ to 6™™ in diameter, and 
* Dr. O. Penzig, in Ann. d, Agria., 1887 (Studi Botanici Sugli Agrumie Sulle Piante 
Affini), Pl. XX XVIII, Figs. 3 and 4, p. 384, has figured and descrived Colletotrichium 
glaosporioides, and so far as can be judged from the illustrations, the fungus has 
every generic characteristic of that upon the Bean. In his Funghi Agrumicoli, 1882, 
p. 66, Fig. 90, Penzig described the same fungus as Vermicularia gicosporioides. 
