These forms of parasite are so numerous, that nearly every species of flowering plant may become the nidus even of several named genera, with many species, or, at least, varieties of them. We here say attacked, because the advent of many of their forms passes under the name of “blight;” a term which at once recognises their injurious tendency.

Whether these epiphytes are the causes of the so-called blighted conditions, or merely their effects, is a subject upon which no little discussion has been expended. We do not, however, mean to re-open the question here; we will only remark, that in all probability this very wide range of the lower tribes of the vegetable kingdom is very variable in these respects.

Again: it will be impossible to enter into details of the different species of epiphytes. We shall hope, therefore, to elucidate their natural history, in so far as the farmer is concerned, by pointing out the more general facts connected with the following forms:—

1.Uredo segetum—Smut or dust-brand of wheat, barley, and grasses.
2.Uredo caries (Tilletia)—Bunt -of wheat.
3.Uredo rubigo—Red gum or red robin
4.Uredo linearis -—Straw-rust, or “mildew”
5.Puccinia graminis
6.[181]Puccinia fabæ—Bean-rust.
7.Æcidium berberidis—Barberry-rust.
8.Cladosporium herbarum—Corn-ear mould.
9.Botrytis infestans—Potato-mould and mildew.
10.Botrytis—Turnip-mildew.
11.Oïdium erysiphioides -Hop-mildew.
12.Erysiphe macularis
13.Oïdium abortifaciens—Ergot of grasses.

1. Uredo segetum, Smut or Dust-brand, is common to barley, and not unfrequent in wheat; in both of which crops it is easily recognised from the affected ears of corn appearing as though they had been powdered over from the sweep’s soot-bag. On closely examining these blackened ears, we find that the whole flower has, as it were, effloresced into a black powder, which, on being placed under the microscope, is shown to be composed of myriads of granules, called by the fungologist spores, in which latter are contained still smaller grains, or sporidia.

These black spores are all washed away by the time the crop is ripe, leaving the stalks bare and grainless, so that the sample suffers no injury from this blight, which, even if present after threshing, would only tend to a slight discoloration of the sample, which is remediable by the smutter. Its chief effect, however, consists in causing the loss of much grain. We have observed it to the extent of as much as an eighth, but usually the diminution is about equal to the amount of seed sown; though it is not improbable that the whole crop may in many cases be greater when the smut is present. Sheep-folding previous to barley, special manuring for this crop, and other causes of increased fertility, are constant causes of the increase of the dust-brand.

2. Uredo caries—Bunt, Pepper-brand, Smut-balls.—This blight differs from the preceding in the fact that in the grain no flower is formed, but its interior becomes filled with a dark powder, which, when viewed under a high magnifying power, is found to consist of granules, with a surface which is rough, and not smooth as in the dust-brand.

In most cases, the whole grains of the ear will be so affected; in others, only a portion of them. They will be gathered in the harvest, and as the diseased grain is readily crushed, the black powder materially damages the appearance of the sample. Nor is this all: this blight has a most disagreeable odour and flavour, both of which are communicated to the sample, and so, besides diminishing the amount of produce, it greatly deteriorates it. Its specific name of caries of course refers to this fact, as also does that of U. fœtida, adopted by Baur, an author to whom we are greatly indebted for information upon these curious productions.

Before considering the remedy for this evil, it will be well to distinguish it from the “purples, ear-cockle, or peppercorn” (vibrio tritici)—a name expressive of its animal origin, and frequently rendered “wheat-eels.” In the purples, the grain is shorter than a healthy wheat grain, irregular in shape (cockled), and purple externally; but its interior is filled with what, to the naked eye, is like very short white cotton-wool. On placing a bit of this woolly substance with the point of a needle on a slip of glass, just touching it with water and submitting it to a high magnifying power, the term “wheat-eel” will at once be seen to be justified; for, if alive, thousands of eel-like creatures will be seen writhing in the fluid.