damp, discoloured, but not by any means mouldy. At length, and rather suddenly, patches of mould, sometimes two or three inches in diameter, made their appearance. These were at first of a snowy whiteness, cottony, and dense, just like large tufts of cotton wool, of considerable expansion but of miniature elevation. They projected from the paper about a quarter of an inch. In the course of a few weeks the colour of the tufts became less pure, tinged with an ochraceous hue, and resembling wool rather than cotton, less beautiful to the eye or a lens, and more entangled. Soon after this darker patches made their appearance, smaller, dark olive, and mixed with, or close to, the woolly tufts; and ultimately similar spots of a dendritic character either succeeded the olive patches, or were independently formed. Finally little black balls, like small pinheads, or grains of gunpowder, were found scattered about the damp spots. All this mouldy forest was more than six months under constant observation, and, during this period, was held sacred from the disturbing influences of the housemaid's broom, being consigned to the master's care with little compunction, but occasionally it became the subject of remarks not altogether flattering either to the wall or the moulds, or the master who was protector and patron of such a wretched mess.

Curiosity prompted us from the first to submit the mouldy denizens of the wall to the microscope, and this curiosity was increased week by week, on finding that none of the forms found vegetating on nearly two square yards of damp wall could be recognised as agreeing specifically with any described moulds with which we were acquainted. Here was a problem to be solved under the most favourable conditions, a forest of mould indoors, within a few yards of the fireside, growing quite naturally, and all strangers; could they all be related, or if not, why should all of them appear on that wall for the first time? Whence could these new forms proceed? Were they a new creation? Were they only other conditions of very common things? Certainly here was material for much reflection, perhaps some speculation. Some of the problems are still unsolved.

The cottony tufts of white mould which were the first to appear had an abundant mycelium, but the erect threads which sprung from this were all for some time sterile (Pl. LXVIII. fig. 1); they were slender, very delicate, jointed, and branched; so interlaced that it was difficult to trace the threads throughout their length, or to separate them from each other. Fertile threads were then developed in tufts mixed with the sterile threads, or individual fertile threads appeared amongst the sterile. These latter were rather shorter and stouter, also sparingly branched, but beset throughout nearly their whole

length with short, patent, alternate (mostly) branchlets. The branchlets were broadest towards the apex, so as to be almost clavate, and the extremity was beset with two or three short spicules (Pl. LXVIII. fig. 2). Each spicule was surmounted by an obovate spore (a) attached to the spicule by its smallest end (Pl. LXVIII. fig. 3). The presence of fertile threads gave the pale ochraceous tint to the tufts already alluded to. This tint was so slight that perhaps it would have passed unnoticed but for the proximity of the snow-white tufts of barren threads. The fertile flocci, it may be from the weight of the spores, were decumbent, hence the fertile tufts were not much elevated above the surface of the matrix.

This is a most interesting mould belonging to the order of Mucedines, but it seemed to agree so little with the characters of any known genus, that, on distributing specimens last year, it was placed provisionally in a new genus under the name of Clinotrichum lanosum; * since then, with the advice of some mycological friends, it has been referred to the old genus Rhinotrichum, as Rhinotrichum lanosum. Without entering here upon the reasons which led to this course, or attempting to discuss generic and specific distinctions, it is sufficient to indicate that the mould in question possessed such positive characters, and was so different from all recognised forms, that it not only had claims to be regarded as a distinct species, but it still remains doubtful whether it should not constitute the type of a new genus.

The mould above described having become established for a week or two, small blackish spots made their appearance on the paper, sometimes amongst thin patches of the mould and sometimes outside them. These spots, at first cloudy and indefinite, varied in size, but were usually less than a quarter of an inch in diameter. The varnish of the paper was afterwards pushed off in little translucent flakes or scales, an erect olivaceous mould appeared, and the patches extended to nearly an inch in diameter, maintaining an almost universal circular form.

This new mould sometimes possessed a dirty reddish tint, but was commonly dark olive. There could be no mistake about the genus to which this mould belonged; it had all the essential characters of Penicillium. Erect jointed threads, branched in the upper portion in a fasciculate manner, and bearing long beaded threads of spores, which formed a tassellike head, at the apex of each fertile thread (Pl. LXVIII. fig. 4).

CLINOTRICHUM, gen. nov. Hyphasma creeping; fertile flocci septate, decumbent, simple, or branched; branchlets alternate, patent, short, bearing at their tips a few spores attached to short spicules; spores simple. Type, Clinotrichum lanosum.-Cooke, Fungi Brit. Exs. No. 356.

For the benefit of the mycologist, we may observe that, although at first reminded of the Penicillium olivaceum of Corda by the colour of this species, it differs in the spores being oblong (Pl. LXVIII. fig. 4 B), instead of globose, and the ramifications of the flocci are different. Unable again to find a described species of Penicillium with which this new mould would agree, it was named Penicillium chartarum.

Almost simultaneously, or but shortly after the perfection of the spores of the Penicillium, other and very similar patches appeared, distinguished by the naked eye more particularly by their dendritic form (Pl. LXVIII. fig. 6). This peculiarity seemed to result from the dwarfed habit of the third fungus, since the varnish, though cracked and raised, was not cast off, but remained in small angular fragments, giving to the spots their dendritic appearance, the dark spores of the fungus protruding through the fissures. This same mould was also found in many cases growing in the same spots amongst Penicillium chartarum, but whether from the same mycelium could not be determined.

The distinguishing features of this fungus consist in an extensive mycelium of delicate threads, from which arise numerous erect branches, bearing at the apex dark brown opaque spores. Sometimes the branches are again shortly branched, but in the majority of instances are single. The spores are septate, sometimes with two, three, or four divisions, many of them again divided by cross septa in the longitudinal direction of the spore, so as to give a muriform appearance. As far as the structure and appearance of the spores are concerned, they are very similar to those of Sporidesmium polymorphum; consequently specimens were published as a variety of that species, but the accuracy of this determination is open to very grave doubts. The mycelium and erect threads are much too highly developed for a good species of Sporidesmium, and certainly so for the species to which they were referred, so that in the "Handbook of British Fungi" it is named Sporidesmium alternaria, for reasons hereafter detailed (Pl. LXVIII. fig. 7).

Preuss has described, in "Sturm's Flora," a species of Alternaria in which the spores are attached end to end in a beaded manner, as in other species of that genus, and the spores themselves are just of the character of the spores of our Sporidesmium, as will be seen by reference to the plate and comparison of figures 8 and 9. Preuss's Alternaria, which he calls chartarum, was also developed on paper, and it is not improbable that it is a more highly perfected form of the Sporidesmium in question. This view is strengthened by the appearance of freshly collected specimens of the Sporidesmium, in which, as

seen by a half-inch objective, the spores seem to be moniliform; but if so, the attachment is so slight that all attempts to see them so connected when separated from the matrix have failed. On one occasion a very immature condition of the Sporidesmium was examined containing simple beaded spores (Pl. LXVIII. fig. c) connected by a short neck. There is therefore some foundation for believing that the spores of this species are at first hyaline, simple, and connected together in a moniliform manner by a short apiculus; but, as subsequent search did not reveal any further corroborative evidence, it can only be considered probable. Finally, Mr. C. E. Broome, to whom specimens of the Sporidesmium were submitted, confirmed the observation that, when seen in situ, the spores seemed to be beaded.

The last production which made its appearance on our wallpaper burst through the varnish as little black spheres like grains of gunpowder. At first the varnish was elevated by pressure from beneath, then the film was broken, and the little blackish spheres appeared. These were, in the majority of instances, gregarious, but occasionally a few of the spheres appeared singly, or only two or three together. As the whole surface of the damp paper was covered by these different fungi, it was scarcely possible to regard any of them as isolated, or to declare that one was not connected with the mycelium of the others. The little spheres, when the paper was torn from the wall, were also growing from the under surface, flattened considerably by the pressure. We shall call this species, for the sake of distinction, Sphæria cyclospora. The spherical bodies, or perithecia, were seated on a plentiful colourless mycelium. The walls of the perithecia, rather more carbonaceous than membranaceous, are reticulated, bringing to mind the same structure in Erysiphe, to which the perithecia bear considerable resemblance. The ostiolum is so obscure that we could not be satisfied of its existence, or whether the perithecia are ruptured when mature. It is rather from analogy than positive evidence that the name of Sphæria is given (Pl. LXVIII. fig. 10). The interior of the perithecia is occupied by a gelatinous substance consisting of long cylindrical sacs or asci, each containing eight globose, colourless sporidia (Pl. LXVIII. fig. 11). These are accompanied by slender branched threads, called paraphyses, supposed to be abortive asci. At first, and for some time, the perithecia contain only a granular mass, at length mixed with paraphyses. The contents of the fertile asci are also at the first granular, and finally the sporidia are perfected.

We have now described, as fully as seemed to be necessary, the four forms of fungi which vegetated during last winter and