Another case of association--for the evidence does not proceed further--was recorded by us, in which a dark-coloured species of _Penicillium_ was closely associated with what we now believe to be a species of _Macrosporium_--but then designated a _Sporidesmium_--and a minute _Sphæria_ growing in succession on damp wall-paper. Association is all that the _facts_ warrant us in calling it. We cannot forbear alluding to one of the species of _Sphæria_ to which Tulasne[m] attributes a variety of forms of fruit, and we do so here because we think that a circumstance so extraordinary should be confirmed before it is accepted as absolutely true. This refers to the common _Sphæria_ found on herbaceous plants, known as _Sphæria_ (_Pleospora_) _herbarum_. First of all the very common mould called _Cladosporium herbarum_ is constituted as conidia, and of this again _Macrosporium sarcinula_, Berk., is considered to be another condition. In the next place, _Cytispora orbicularis_, Berk., and _Phoma herbarum_, West., are regarded as pycnidia, enclosing stylospores. Then _Alternaria tenuis_, Pr.,[n] which is said to be parasitic on _Cladosporium herbarum_, is held to be only a form of that species, so that here we have (including the _perithecia_) no less than six forms or phases for the same fungus. As _Macrosporium Cheiranthi_, Pr., often is found in company with _Cladosporium herbarum_, that is also open to suspicion. We have adduced in the foregoing pages a few instances which will serve to illustrate the polymorphism of fungi. Some of these it will be observed are accepted as beyond doubt, occurring as they do in intimate relationship with each other. Others are considered as scarcely so well established, but probable, although developed sometimes on different species of plants. Finally, some are regarded as hitherto not satisfactorily proved, or, it may be, only suspicious. In this latter group, however much probability may be in their favour, it can hardly be deemed philosophical to accept them on such slender evidence as in some cases alone is afforded. It would not have been difficult to have extended the latter group considerably by the addition of instances enumerated by various mycologists in their works without any explanation of the data upon which their conclusions have been founded. In fact, altogether this chapter must be accepted as illustrative and suggestive, but by no means as exhaustive. [A] De Bary, in "Quarterly German Magazine" (1872), p. 197.