| # MICRO-FUNGI: WHEN AND WHERE TO FIND THEM by ## Thomas Brittain 1882

## JULY IT must be understood, as I have previously intimated, that any enumeration of leaf-fungi as belonging to any particular month must be accepted as merely a convenient mode of conveying to the student what he should look for as most likely to be found. Nature does not accept any such limitations, and is only influenced by local conditions and by climate. For instance, the brand upon the Adoxa muscatellina I have usually classed with the fungi for June, and it is now in July in perfection, it is known as Puccinia saxifragarum. Similar circumstances arise continually in every attempt at classification as to time. I referred in the May paper to the genus Trichobasis. There are now various species of the genus to be met with, some, as the T. violarum, on the field violets, are very common, as is also T. cichoracearum on the composite plants. Various other species also may now be met with, and are easily known and identified on microscopic examination. There are numerous Aecidiacei now to be met with, the one on garden mint as also on wild mint is very common; the same clustercup Ae. Menthae is found upon both, but is much more common on the garden mint than the wild. It grows chiefly upon the stalks, but occasionally it is to be found upon the leaves. There is one other clustercup of rare beauty which I have found this month, Ae. Behenis, or Bladder-campion clustercup. This fungus is rare as it is beautiful, and I have only found it twice, once in Wales and once in Devonshire, and in both cases on the sea coast. Amongst the white micro-fungi, for we have them of all colours, there is one which I hunted for during almost a generation, and I have never met with in the north of England. It is Cystopus candidus on cabbage. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 10 Fig. 198-200 I did, however, meet with it in Devonshire, in 1879, and in the following autumn at Deganway, near Conway in Wales. Strange to say there is the exactly same species of fungus which grows upon the Shepherds' Purse in great plenty almost everywhere. At certain times the plant and the fungus are alike common. There are other species of this genus which will often be met with by the industrious student, one of which is rarely found in perfection or in any considerable quantity. I allude to the Goat's beard cystopus, known as Cystopus cubicus, or Goat's beard white rust. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 10 Fig. 201,202,210 This I have found in small quantity near Southport on many occasions, but I dont imagine that it is ever developed in large quantity. On cabbage, when cystopus is found on that plant, it appears in patches often comparatively large, and they have the appearance of dabs of whitewash. There is another genus to which I desire to refer, although several of the species are, from their surrounding conditions, difficult to meet with. Others cannot well be overlooked. Amongst the latter are Tilletia caries, the bunt of wheat, Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 5 Fig. 84-91 and Ustilago carbo, corn smut, so common on oats and barley. Amongst the more minute species are those that grow upon the anthers of various flowers. Ustilago Antherarum I have but once found; it was when I was botanizing in Dovedale some years ago; it was on Silene inflata. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 5 Fig. 102-104 In the summer of 1880, I for the first time met with Ustilago Kuehniana at Urmston on anthers of common Sorrel, Rumex acetosa. Ustilago longissima on grass I have frequently met with, but only in one locality, near Nortbenden in Cheshire; but I don't suppose the smut is confined to any county whatever. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 5 Fig. 105-107 When seen upon the leaf it wears the appearance of fine black lines as if ruled with a pen. There are various other species on grass, as also on numerous plants, and they are all worthy of being sought after by the reader. These very minute organisms require a good lens of high power, and also of good defining quality, in order to distinguish the different species. I have often employed one of Beck and Beck's one sixth for this purpose, and even then I have had to go over the specimen frequently before I could come to any satisfactory conclusion. Now is the time to begin to look out for Peronospora. They generally assume the form of delicate white threads thickly set upon the leaf of the plant, giving it a somewhat glazed appearance. One of this genus is the great enemy of our favourite vegetable the potato, and is the especial dread of the market gardener. If the season be wet, this well-known mould Peronospora infestans, as it is named, is very likely to be developed towards the latter end of this month, or early in the next. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 14 Fig. 264 A preliminary decay of the leaf is indicated by the appearance of brownish spots, and on the examination of the leaf in this condition, the mould, if existing, will be found close to, and sometimes partly upon the spots. Unfortunately this pest is far too common amongst potato fields in wet seasons. In August, 1880, I met with an enormous quantity of the fungus in potato fields at Urmston, and, had not the farmers took the wise step of at once digging up the tubers, the destruction would have been fearful. Thoughtless delay in the farmer frequently gives the fungus time to get down to the potato itself, when the tuber quickly becomes unfit for human food. The way by which this rapid change comes about, is a good study for the microscopist, but is too long a story for me to tell on the present occasion. The species of this genus are numerous, and new ones are frequently being found; some ten or a dozen such are well recognised and admitted as true Peronospora that were not known a dozen years ago. The Rev. Mr. Vize, of Forden, Welshpool, has the honour of bringing some of these to the knowledge of botanical students. If the reader desires, he may soon collect a considerable number of the Peronspora, for they are constant visitors upon a large number of our plants. Our old friend Ranunculus ficaria, which has already given us a beautiful clustercup Aecidium ranunculacearum, Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 2 Fig. 12-14 and the smut Uromyces ficariae; Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 7 Fig. 156-157 supplies us with a Peronospora, P. ficariae. The wood anemone also gives us a clustercup, Aecidium leucospermum Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 1 Fig. 4-6 and a smut Puccinia anemones Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 4 Fig. 64-65 now presents us with the Peronospora pygmaea. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 15 Fig. 267 In this way numerous plants during the year come forward from time to time with their contributions for scientific study. I think I can now best assist the student by giving a list of the more common Peronospora, a familarity with which will tend to educate the eye, and prepare him for the discovery and identification of the more rare ones. The more common ones, speaking from my own experience, are :- Peronospora nivea (Parsnip mould), on Umbelliferae. P. gangliformis (Lettuce mould), on Lettuces and other compositae Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 14 Fig. 265 P. viciae (Pea mould), on Peas, &c. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 10 Fig. 212 Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 15 Fig. 266 P. violae (Violet mould), on leaves of common Violet. P. urticae (Nettle mould), on leaves of Nettle. P. obliqua (Dock mould), on leaves of Sorrel and Dock. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 16 Fig. 269 Amonst the Aecidiacei we have several interesting fungi, known as Peridermiums, one of which Peridermium pini may be found this month on leaves of Scotch fir. Rust, Smut, Mildew & Mould - M.C.Cooke - Plate 2 Fig. 27 I cannot but think it very rare, as I have never been able to meet with it, although my attempts in that direction have been continued from year to year ever since my study of these wonderful plants began. Let the student, however, take such opportunities as he may have for the examination of the tree, and it is not improbable that he may be more fortunate than the writer.

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