III. Æcidium.—Particular organs which engender stylospores, and which produce—
IV. Uredo, the second form of the stylospores, and later spores (No. I.), which are always associated with Uredo in the same pustule. The spores and stylospores of Uredo come also upon the old mycelium, which has previously produced Æcidium. The Uredo stylospores always produce Uredo, and true spores.
CHAPTER IV.
MILDEW AND BRAND.
DR. WITHERING’S “Arrangement of British Plants” in 1818 reached its sixth edition. This is less than half a century ago, and yet the whole number of species of Fungi described in that edition was only 564, of which three hundred were included under the old genus Agaricus. Less than eighty of the more minute species of Fungi, but few of which deserve the name of microscopic, were supposed to contain all then known of these wonderful organisms. Since that period, microscopes have become very different instruments, and one result has been the increase of Withering’s 564 species of British Fungi to the 2,479 enumerated in the “Index Fungorum Britannicorum.” By far the greater number of species thus added depend for their specific, and often generic characters, upon microscopical examination. The proportion which the cryptogamic section bears to the phanerogamic in our local Floras before 1818, now almost involuntarily causes a smile. Even such authors as were supposed to pay the greatest possible respect to the lower orders of plants could never present an equal number of pages devoted to them, as to the higher orders. Relhan, for instance, only occupies one-fifth of his “Flora Cantabrigiensis,” and Hudson one-fourth of his “Flora Anglica,” with the Cryptogamia. At the present time, it will be seen that, with a liberal allowance for “hair-splitting,” the number of British species of flowering plants scarcely exceeds three-fourths of the number of Fungi alone, not to mention ferns, mosses, algæ and lichens, and yet we have no “Flora” which contains them, and but a minority of our botanists know anything about them. If we need excuse for directing attention to some of the most interesting of these plants, let the above remarks suffice in lieu of formal apology.
“Mildew” is just one of those loose terms which represent no definite idea, or a very different one to different individuals. Talk of mildew to a farmer, and instantly he scampers mentally over his fields of standing corn in search of the brown lines or irregular spots which indicate the unwelcome presence of Puccinia graminis, known to him, and to generations of farmers before him, as “mildew.” Try to convince a Norfolk farmer that anything else is “mildew,” and he will consider you insane for your pains. Speak of mildew in your own domestic circle, and inquire of wives, or daughters, or servants, what it means, and without hesitation another, and even more minute species of fungus, which attacks damp linen, will be indicated as the true mildew, to the exclusion of all others; and with equal claims to antiquity. Go to Farnham, or any other hop-growing district, and repeat there your question,—What is mildew?—and there is every probability that you will be told that it is a kind of mould which attacks the hop plant, but which differs as much from both the mildew of the farmer and the laundry-maid as they differ from each other. The vine-grower has his mildew, the gardener his mildewed onions, the stationer his mildewed paper from damp cellars, the plasterer his mildewed walls, and in almost every calling, or sphere in life, wherever a minute fungus commits its ravages upon stock, crop, or chattels, to that individual owner it becomes a bug-bear under the name of “mildew.” Reluctantly this vague term has been employed as a portion of the title to this chapter, but it must be limited in its application to the “mildew of corn,” known to botanists as Puccinia graminis, and not to include the numerous other microscopic Fungi to which the name of mildew is often applied.
The origin of this term and its true application may undoubtedly be traced to mehl-thau, “meal dew.” A singular proof of the ignorance which prevails in regard to all the fungal diseases of corn, may be found in the fact that at least one of our best etymological dictionaries states that the mildew in corn is the same as the ergot of the French. Had the writer ever been a farmer, he would have known the difference; had he ever seen the two, he could scarcely have made such a mistake. It is barely possible for him ever to have heard the ergot of grain called by the name of mildew.
How long this disease has been known, is an unsolved problem. About the middle of the last century a tract was published on this subject in Italy, but this was probably not even the first intimation of its fungoid character. Before such conclusion had been arrived at, men may have struggled in the dark, through many generations, to account for a phenomenon with which they were doubtless familiar in its effects. In 1805, Sir Joseph Banks published his “Short Account,” illustrated by engravings from the inimitable drawings of Bauer, whereby many in this country learnt, for the first time, the true nature of mildew.
Plate III.
W. West imp.