TURNIP MOULD.—Since the advent of the potato murrain a similar disease has been witnessed, though more limited in its extent, amongst Swedish turnips, commencing in little waved irregular lines following the course of the vessels, around which spots are formed by the deposition of dark granules in the same manner as in the potato. In this instance, the leaves apparently are first attacked in a similar manner by a species of mould or _Peronospora_ allied to the one already described, but which has been long known as parasitic upon cruciferous plants, to which the turnip belongs. This species, termed _Peronospora parasitica_, is white in all stages of its growth. It is much more branched, and the branches are comparatively shorter than in the potato mould, and the tips of the branches are bifid (fig. 262). The acrospores are very large and globose, features also which distinguish this mould from the last. A short time since we were called to witness a bed of splendid cauliflowers, which had, up to that time, been the pride of their cultivator; but, alas! their glory was threatened with speedy annihilation, for in nearly every instance the lower leaves had become more or less covered on their upper surface with yellow spots, and beneath glaucous with the mould we have been describing. The diseased leaves were all immediately removed, but we fear without success, although no positive information has since reached us. The almost unnatural vigorous green of the leaves, prior to the appearance of the mould, is not at all an uncommon occurrence: this phenomenon has been noticed in the ears of corn, in which every grain was soon afterwards filled with spores of bunt. This species was at one time believed to be parasitic on the “white rust,” from which circumstance its specific name was derived. More precise examination proves that it sometimes occurs where no white rust is present, and therefore its parasitism is imaginary. The suckers in this species are large and penetrate the cells, often entirely filling them. This feature is sufficient to distinguish the mycelium of the mould from that of the “rust.” The turnip mould occurs on many cruciferous plants, and especially on the shepherd’s-purse, as well as upon the different varieties of cabbage and its more immediate allies.