1375. ] LITHOSPERMUM PROSTRATUM.—THE FUNGUS OF THE POTATO DISEASE. 171 
lumps of pure clay rather than not have a bottom sufficiently retentive of 
moisture. 
I need not enlarge upon those cases few and far between, where the natural 
drainage is so good, and the soil consists of deep and friable loam, that it only 
needs to be trenched up, and the border is ready for planting ; but in the course 
of time exhaustion must take place, and such natural borders will have to be 
subjected to the same routine of management as is required in the case of those 
most carefully prepared.— John Cos, Beclleaf. 
LITHOSPERMUM PROSTRATUM. 
S ITHOSPERMUM prostratum is at once one of the most beautiful and useful 
amongst hardy plants ; the deepest-hued and most pleasing amongst blue 
flowers. It is a plant that has often been noticed, and very deservedly so, 
but I allude to it again with the view of publishing yet another feature of 
merit, which may be added to those more generally known. 
Lithospermum prostratum is a plant of recumbent growth, the stems lying 
flat on the ground, evergreen, a native of France, and introduced amongst us 
some half-century ago. I have it flowering beautifully on the northern side of, 
and partly under, a huge Weeping-willow Tree—in fact, in a special position, 
where I have planted the Royal Fern, because I thought in this arid locality it 
would succeed best in a shaded damp and somewhat enclosed shrub-hidden 
spot. If, then, this lovely plant will succeed so well under such circumstances 
may it not be used freely in all sites and in most situations, than which a higher 
certificate of usefulness cannot be tacked to the character of any plant ?— 
William Earley, Valentines. 
*** It grows and blossoms very freely in the deep, sandy, and peaty soils of 
Woking and of Weybridge, forming large flat evergreen patches, and blooming most 
profusely from the early summer onwards. It is often falsely called Lithospermum 
fruticosum. 
THE FUNGUS OF THE POTATO DISEASE. 
9 j (?0R years it has been the settled conviction of our leading naturalists that 
(lip the insidious disease which for some thirty years has more or less each 
season damaged our potato crops, was due to the attacks of a microscopic 
5 fungus called Peronospora infestans —the fungus itself probably owing its 
destructive prevalence to certain warm moist conditions of climate which occur 
during the summer months, and favour its development. The life-liistory of this 
Potato fungus was, however, but imperfectly ascertained, and one link in the chain 
remained unknown until recently discovered by Mr. Worthington G. Smith, in 
examining specimens of what was at first supposed to be a new disease attacking 
the Potato. This link is what is called the resting-spore, by means of which the 
vitality of the plant is continued through the winter, after the mycelial threads 
and summer spores have perished, Mr, Smith soon arrived at the conclusion 
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