132 
THE FLOEIST AND POMOLOGIST. 
[ September, 
able crops, and that in consequence an inquiry 
into its cause was instituted by order of the 
Government. In Russia the disease is known 
as Kapustnaja lcila (Kapustci — cabbage, Icila — 
hernia). M. Woronin was not long in dis¬ 
covering that the cause of the disease was a 
parasitic fungus, named by him Plasmidio- 
phora Irassicce , since the disease consists in an 
alteration of the plasmodic contents of the 
cells. As the result of repeated observations, 
carried on through 1875, 1876, and 1877, the 
life-history of this new parasite has been, in 
great measure, traced out. 
One most striking feature in the new plant, 
as already hinted, is indicated by its generic 
name, Plasmidiophora. On examining the 
tissue of an old, well-developed knob off a 
club-root, most of the parenchymatous cells 
will be found enlarged, their starchy contents 
gone, and they themselves gorged with a mass 
of spore-like bodies. By the ordinary disinte¬ 
gration of the cellular tissue, these spores will 
get released, and after a lapse of six days, out 
of each spore will proceed the whole of its 
contents, which, colourless, but nucleated, will 
move about like so many minute Amcebae. 
These plasmodia will then attach themselves 
to the delicate root-hairs of the nearest young 
cruciferous seedling, penetrate the cells, and 
thus contaminate the cellular tissue of the root, 
which, as a consequence, in process of time will 
develope the clubbed appearance on the surface. 
“ If cabbage or turnip seeds be sown in a 
watch-glass, and supplied with distilled water, 
and shortly after the first appearance of ger¬ 
mination a number of spores of Plasmidio- 
phorci brcissicce be added to the water, these 
will at first be found to float freely on the 
water, but sooner or later will sink, and attach 
themselves to the delicate root-hairs of the 
little seedlings; and in this way their whole 
history, so far as now known, can with facility 
be traced.” 
Referring recently to this subject in the 
Gardeners’ Chronicle , the Rev. M. J. Berkeley 
thus describes the changes which take place in 
the cells :—At a very early stage of growth, 
some of the component cells of the root become 
very much enlarged, and filled with a granular 
protoplasm, which soon becomes differentiated, 
and at last gives birth to multitudes of spherical 
spores. The most interesting matter now occurs, 
—the spores germinate, but instead of producing 
threads, as the generality of fungi, they give rise 
to Ameeba-like bodies, closely resembling those 
of the little dusty fungi known under the name 
of Myxogastres, of which a good example is the 
yellow dusty plant so common in hot-liouses 
where tan is used. If these germinating spores 
are now sown, the young seedlings are quickly 
affected. Sometimes every rootlet becomes 
altered in shape, at other times the change is 
partial, but in a short time the disease acquires 
the usual appearance of clubbing. 
Many attempts have been made to find a 
remedy, but they have been hitherto unsuccess¬ 
ful. The practical results which M. Woronin 
deduces from his observations are as follows :— 
The absolute extirpation of the disease appears 
to be impossible, since any remedy which 
might be useful is quite as likely to kill the 
plant as the parasite. The following sugges¬ 
tions are, however, offered with a view to limit¬ 
ing its effects :— 
1. The principal means of at least alleviat¬ 
ing the disease is to burn everything which is 
likely to propagate it, and as it has been 
proved that it can be propagated by the spores, 
our duty in this matter is plain. Old plants 
thus affected are often allowed to lie about in 
the spring, but they should be carefully cleared 
from the ground and immediately burnt. 
2. A careful selection of plants from the 
seed-bed should be made, and none used which 
are not perfectly clear. It has been usual 
under such circumstances merely to pinch off 
the affected rootlets, but this is not sufficient, 
as the disease may exist in other rootlets, 
which are apparently free. 
3. A well - considered rotation of crops 
should be adopted. It is suggested that the 
ground should not be used a second time for 
Cabbageworts till after the lapse of two years. 
CROTON NOBILIS. 
S HIS very fine variety of Croton —more 
correctly, though less familiarly named 
Codiceum —was sent out by Messrs. Veit ch 
and Sons, of Chelsea, with the accompany¬ 
ing description :—“ A beautiful variety, with 
long pendulous lanceolate leaves, richly coloured 
with many tints. The colours are crimson, yellow, 
and green in many shades, the crimson being 
predominent in the stems, the footstalks of the 
leaves, and in many of the midribs, where it is 
bordered by bands of deep golden-yellow. In 
