176 Annual Report for 1905 of the Consulting Botanist. 
unfortunately, is not yet known to have produced any fructifi- 
cation, though the formation of sclerotia has been observed 
and described by other investigators. ■ 
A well-known species ( R . violacea Tul.) causes the death 
of lucerne and clover. Dr. J. Kuhn, in 1858, in his book, 
Krankheiten dev Gewachse , page 224, gives an account of the 
same fungus on potatoes, and gives to it the specific name 
solani. From comparison of the description of R. violacea and 
R. solani , no morphological differences can be discovered, 
though Kuhn gave to it a new name. It is important to record 
that the farmer informed me that a crop of lucerne had been 
grown last year in the field where the potatoes grew T . From 
the identity of the mycelium in the lucerne and the potato, 
and from the connection of these two crops, there can be no 
doubt that it is the same fungus that attacked these plants, and 
consequently that the name given by Kuhn — R. solani — must 
be considered as a synonym of R. violacea. 
How far the specific names of other Rhizoctonice , as 
R. Allii Grev., R. Batata Fr., and R. Mali D.C., represent 
different species must be determined by further investigation. 
Cultivation experiments at the laboratory for the purpose of 
producing fructification havq hitherto failed, as with other 
investigators, but the following additional observations may be 
recorded. 
In my visit to the field it was found that, the soil was of a 
light sandy and gravelly composition. It may be noted that 
the plants — lucerne, onions, and yams — on which Rhizoctonice 
have been noticed prefer a light sandy soil. 
The fungus occurred in the low-lying damp portions of 
the field, where its attack was very conspicuous. The haulm 
of the potatoes to a height of six inches and the surrounding 
soil was covered with a thick felt of the reddish mycelium. 
This spread below the surface, covering all parts of the sub- 
terraneous portions of the plants and the tubers, and permeated 
the soil. The fungus grew with great rapidity, spreading over 
and entangling all plants in the moist portions of the field, 
but only became noticeable late in the year, when moisture 
abounded. 
The mycelium spreads entirely in and on the epidermal cells. 
The sclerotia, however, scarcely pass beyond the sub-epidermal 
cells (see Fig. 3, E). No penetration of the potato by the 
superficial mycelium beyond the epidermal cells was observed ; 
the potatoes were all in this stage firm and intact. The my- 
celium, however, rapidly takes possession of the interior where 
a rupture of the skin occurs ; then it loses its dull red colour, 
becoming in a mass, yellowish ; but single filaments are nearly 
colourless. The mycelium thus entering the tubers did not 
