46 
EXTERNAL CHARACTERS. 
The fungus may attack any part of the plant: when on the leaf it 
occurs in the form of a brown spot, which may increase in size until the 
whole leaf is either diseased or withered; when on the petiole, the leaf and 
part of the petiole beyond the point of attack shrivel up at once; when 
at the base of the petiole, on the young unfolding leaves, or on the main 
stalk of the plant itself, the fungus quickly runs down to the root and 
kills the plant. Wherever the stem or petioles are attacked they 
shrivel up; all flow of sap is checked and the part of the plant or leaf 
beyond this point must succumb. If the plant is very dry, the diseased 
parts dry up, but if grown in a moist place the trouble is aggravated by 
swarms of bacteria that attack the diseased portions and, instead of dry¬ 
ing up, the plant seems to perish by a kind of wet-rot. When the plant 
lias attained some size and firmness of texture, the surface of the petiole 
or stem sinks in at the point of attack, forming a distinct flattening or 
even a hollow. The color of these spots varies from a light-yellowish 
brown to black. Frequently the centers of the spots are rust-color, be¬ 
coming entirely black later. 
BOTANICAL CHARACTERS. 
The disease is due to a fungus closely resembling the well known bean 
rust [Colletotrichium Lindemuthianum, (Sacc. and Magnus) Brios. & 
Cava.], but the brown setae or bristles which accompany the spores 
are much more plentiful than in the bean fungus. No published record 
of the fungus could be found and I have designated it Colletotriehium 
altlicece.* In structure the fungus resemles a Glceosporium except for 
the presence of the bristles in the fruit pustules. The spores of Col- 
letotrichium in general are either acicular and curved or oblong. This 
belongs to the latter class. 
The basidia and spores are formed beneath the cuticle, which is finally 
rutured (fig. 5); the setae appear after the basidia but very early in the 
history of the fungus. On the older spots they may become so numerous 
as to make the pustules appear like minute black tufts of hair, and to 
give the center of the spots on the stems a black color. 
The spores, produced by constriction from the stalks or basidia (fig. 2), 
are unicellular, sometimes becoming once septate at the time of germina¬ 
tion. They germinate quickly in nutrient solutions, and by the use of a 
mixture of hollyhock decoction in agar agar the fungus may be brought 
Colletotriehium althcew, n. s.—Epiphyllous and caulicolous, eruiupent, forming 
brown spots on the leaves and light-yellowish brown to black sunken spots on the 
petiole and stalk. Spores irregularly oblong, frequently with a light spot iu the cen¬ 
ter, granular, colorless singly, flesh-colored in mass, 11-28 by b/u. Basidia colorless, 
regularly cylindrical, tapering slightly or rounded at the apex, at least slightly 
longer than the mature spore, borne on a thin layer of pseudo-parenchyma, simple, 
but may branch if placed in excess of moisture (fig. 2). Seta? dark brown, abundant, 
once or twice septate, usually colorless below, 60-109 by 3-5^, appear later than the 
basidia. 
