* Shield the young harvest. l. 511. Linneus enumerates but four diseases of plants; Erysyche, the white mucor or mould, with sessile tawny heads, with which the leaves are sprinkled, as is frequent on the hop, humulus, maple, acer, &c. Rubigo, the ferru∣gineous powder sprinkled under the leaves frequent in lady's mantle, alchemilla, &c.

Clavus, when the seeds grow out into larger horns black without, as in rye. This is called Ergot by the french writers.

Ustulago, when the fruit instead of seed produces a black powder, as in barley, oats, &c. To which perhaps the honey-dew ought to have been added, and the canker, in the former of which the nourishing fluid of the plant seems to be exsuded by a retrograde motion of the cutaneous lymphatics, as in the sweating sickness of the last century. The latter is a phagedenic ulcer of the bark, very destructive to young apple-trees, and which in cherry-trees is attended with a deposition of gum arabic, which often terminates in the death of the tree.


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