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

## NOVEMBER AS November approaches the leaf-fungi have with but few exceptions withdrawn from the scene, but other minute members of the great fungus family crowd upon us and claim our attention. The innumerable leaves, lately green or beautifully tinted with autumnal shades, are now scattered about in all directions. The vegetable vitality is extinct, but the dead leaf becomes the home of countless organisms. In its gradual decomposition it brings into life a new world of interesting plants, all deserving of microscopic study. There is nothing upon the leaf to indicate the existence of the former leaf-fungi except an opening or fracture in the leaf itself. The leaf tissue has in part been consumed by the parasite, and the millions of spores have been wafted away by the wind to find a resting place until another summer, when they may originate a renewed life. Now there is no scarcity of fallen leaves, for country lanes and woody districts are paved with them. If we pick up a few we soon discover a marked, difference in their surface appearance. Some have distinct black patches upon them, the marks of a decided fungus, while others have but microscopic hints of the possibility of organic life. The patches I speak of are sometimes so arranged upon the leaf of the sycamore as to form a beautiful artistic pattern; at other times irregularly broken up into large and small patches. In all oases they are intensely black and have a shining undulating surface so that they are easily recognised. The black patches on the sycamore are caused by a fungus known as Rhytisma acerinum, and may be met with in woods every autumn in great quantity. I shall never forget my first find of this well-known fungus in a wood at Chelford, early in my microscopic study. Since then, I have frequently met with it. Willow leaves furnish us with another Rhytisma, R. salicinum, and the nettle another, R. urticae, but these, although easily seen, are not so conspicuous as R. acerinum. There is one other to which I must refer, namely, Rhytisma maximum, which makes its home upon branches of the willow, and when in good condition is a most interesting object. Then the spores in asci may be easily obtained and prepared for microscopic inspection. I have always been more or less disappointed in the examination of other Rhytisma, but never with this. It may he known by its shining surface, but the dimpled characteristic of other Rhytisma is absent. The genus Dothidea should now be looked for. Various of them have made their appearance earlier, but may linger on to the end of the year. The one on the rush, D. junci, is an annual visitor, and may now he met with on the margins of pools where rushes love to grow. Another, which is very common, is D. filicina, bracken Dothidea. Almost every stem of Pteris aquilina is more or less infested with this fungus. Some of the Dothidea grow on decayed herbaceous stems, as D. striaeformis. Gooseberry branches are sometimes infested with Dothidea ribesia. Other plants become the homes of other Dothidea, but it is not desirable that I should occupy more time with this genus. The Phacidiacei, of which there are numerous species, and some of which may be easily found on dead leaves. On the holly leaves two species are frequently met with. In woods where the holly is plentiful, the dead leaves of the trees in winter are scattered about in thousands, and almost every leaf is beautifully spotted over with the conspicuous black fungus. The two species I refer to are Phacidium ilicis and P. ilicis pulveracea. Leaves of other plants, now dead on the ground, are equally the habitats of members of this family. What I have said must be accepted as an indication of an interesting field of research to the student. There is a small, bright yellow or orange fungus to he found on damp old twigs and stumps in the shape of rounded spots. After a long continuance of wet weather this is so abundant at times that it cannot be well overlooked, and more especially about this season. It is Tubercularia vulgaris. It is also found on dead twigs upon the living tree. I have many times found it thus in Hough End Clough, within about a mile from Alexandra Park, Manchester. If examined, it is found to consist almost entirely of a mass of countless conidia. I have found November the best time to look for this fungus, and when I have set out on an expedition for that purpose I have never failed to secure what I wanted. This fungus is, however, but the early condition of a more interesting plant, known as Nectria cinnabarina, in its perfect condition, and I have sometimes found it when the two conditions could be distinctly seen on the same stem, and when the change from the early state of the fungus to its perfect condition was taking place. I have at present specimens in my herbarium of that character by me which I obtained some years ago. The Nectria belong to the Sphaeriacei, as also do the Dothidea, spoken of above, having spores in asci, and it requires a good lens to define them well. A fourth or a sixth is the most suitable power for the purpose. The industrious student will meet with numerous other micro-fungi during the month equally interesting with those to which I have referred, but I have said enough to point out the vast field of research which lies before him, and I hope I have also said sufficient to stimulate his industry in the pursuit of a study, than which none is more delightful, nor does any provide for him a more ample reward. Pages from The Northern Microscopist No. 11 November 1881

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