IOOO 
Journal of Agricultural Research 
Vol. V, No. si 
b , c, d , e, /, <7, &). This is observed only when the fruitings of the fungus 
are seen in a dry state. However, when placed in a drop of water or in 
any other liquid, the chains of spores break up and scatter over the liquid. 
The spores (conidia) are i-celled, hyaline, with a greenish tinge, but never 
dark or brown. They measure from 15 to 20 by 4 to 6ju. Sometimes a 
germ tube is produced at the tip of the conidiophore which later bears 
spores (PI. LXXVII, fig. h, /, k, 0 , p). Broken-off mycelial cells are 
also capable of germinating. In this case a germ tube upon which 
spores are formed is first produced (PI. LXXVII, fig. b). The spores 
readily germinate in water or in any nutrient medium (PI. LXXVII, fig. 
m, q y $, v , x , y, z). 
An attempt was made to determine whether M. infuscans would also 
cause a rot of the interior of the sweet-potato root. Inoculations made 
with pure cultures of the fungus in slits made with a sterilized and cooled 
scalpel showed the organism incapable of causing a rot of the root. It 
was thought that perhaps the starch or the sugar was detrimental, but 
the fungus grows well on a starchy medium prepared according to Smith 
(6, p. 196), although not so well on media rich in sugar. It seems prob¬ 
able that neither the sugar nor the starch restricts the growth of the 
organism to the epidermis only, but this is done by the enzyms of the 
host. 
TAXONOMY OF THE FUNGUS 
The name u Monilochaetes infuscans ” meaning black bristly Monilia, 
given by Halsted to the soils tain fungus, remarkably describes the main 
features of the organism. However, Halsted failed to describe fully 
either the species or the genus. Saccardo (5) barely mentions the fungus. 
Neither Engler and Prantl (2) nor Clements (1) nor any other systematic 
writer on fungi record the genus Monilochaetes. The description given 
by Stevens (7, p. 597) is incomplete. It was probably taken from 
naturally infected material, where the chains of conidia are seldom, if 
ever, noticed, since they are partially broken off with the rubbed epi¬ 
dermis. The conidiophores in such material are often broken down or 
wanting. From the present studies it seems that the writer is warranted 
in retaining the names of both the genus and the species of Monilochaetes 
as used by Halsted. Harter (4), too, decided to retain this genus. The 
description from a pure culture follows. 
Monilochaetes infuscans E. and H. 
Spores borne in chains which readily break up; conidia hyaline to green¬ 
ish, guttulate; conidiophores black, several septate; mycelium first 
hyaline, then darker with age. The submerged mycelium swells irregu¬ 
larly. Conidiophores, 100 to 300 by 3 to 7/1; conidia, 15 to 20 by 4 to 6/z. 
The fungus is a very slow grower on artificial media. Parasitic on the 
sweet-potato root, causing a brown, blotched disease of the epidermis. 
