57 
to the upper part of the beetroot, and originating from rootlets or 
leaves that are inoculated by the fun.-tis, which in the- first instance 
enters an epidermal cell causing it to swell, and subsequently pro- 
moting rapid division ami multiplication of surroundiiii,' ci lis, 
until eventually an irregularly formed mass of tissue results. 
When fully developed these outgrowths attain a large size, and 
when cut open present a cavernous or spongy appearance inside, 
the cavities being tilled with masses of -lark brown, thick-walled 
resting-spores, resulting from the conjugation of male and female 
cells, borne on distinct hyphae or strands of mycelium. 
The mature resting-spores are large, with a smooth, thick, dark 
brown wall, elliptical, and are produced at the tips of very slender 
hyphae which have a globose, colourless swelling just below the 
insertion of the resting-spore. 
Quite recently, the fungus under consideration, or one very 
closely allied, has attacked potatoes in this country, causing coarse, 
scabby outgrowths on the surface of the tubers. 
Prevent i re mrd.-ours. — Diseased plants should lie removed and 
burned the moment they are observed ; if allowed to remain and 
rot on the ground, the liberated resting-spores would endanger 
future crops. 
White Rust. 
(Cystopua hliti, De Bary.) 
This fungus has only hitherto been observed on sugar-beet in 
one locality in the United States, but as allied species often prove 
destructive to other plants, especially those belonging to the 
Cruciferae, such as cabbage, radish, horse-radish, &c, it is possible 
that the mangold and beet may also surfer when attacked under 
conditions favourable for the rapid extension of the parasite. 
The disease is indicated by the presence of pure white shining 
slightly raised spots about one line across on both surfaces of the 
living leaves. These patches constitute the conidial or summer 
form of fruit, and are developed below the epidermis of the leaf, 
which becomes ruptured when the spores are mature. The spores 
germinate quickly when placed in water or on a damp surface ; 
hence those that are washed by rain or blown on to the surface of 
a damp leaf soon give origin to a new rust pustule, which in turn 
liberates spores. 
Resting-spores or oospores are also formed on the mycelium of 
the fungus present in the tissues of the leaf ; these remain in an 
unchanged condition until the following spring, when they ger- 
minate, and if young beet or mangold happen to be present, inocu- 
lation follows and the conidial condition of the fungus is the 
Preventii 
the fungus grow w 
Candidas— infesting crucifers, is known to attack plants only 
during the seedling stage, and if the same rule holds good in the 
present instance, diseased plants could be removed when the 
young plants are thinned out. Old diseased leaves should not 
be allowed to remain on the ground, 
