_Hyphomycetes_ are widely diffused; some species are peculiarly cosmopolitan, and all seem to be less influenced by climatic conditions than the more fleshy fungi. The _Sepedoniei_ are represented by at least one species wherever _Boletus_ is found. The _Mucedines_ occur everywhere in temperate and tropical regions, _Penicillium_ and _Aspergillus_ flourishing as much in the latter as in the former. _Botrytis_ and _Peronospora_ are almost as widely diffused and as destructive in warmer as in temperate countries, and although from difficulty in preservation the moulds are seldom represented to any extent in collections, yet indications of their presence constantly occur in connection with other forms, to such an extent as to warrant the conclusion that they are far from uncommon. The _Dematiei_ are probably equally as widely diffused. Species of _Helminthosporium_, _Cladosporium_, and _Macrosporium_ seem to be as common in tropical as temperate climes. The distribution of these fungi is imperfectly known, except in Europe and North America, but their occurrence in Ceylon, Cuba, India, and Australasia indicated a cosmopolitan range. _Cladosporium herbarum_ would seem to occur everywhere. The _Stilbacei_ and _Isariacei_ are not less widely diffused, although as yet apparently limited in species. _Isaria_ occurs on insects in Brazil as in North America, and species of _Stilbum_ and _Isaria_ are by no means rare in Ceylon.
The _Physomycetes_ have representatives in the tropics, species of _Mucor_ occurring in Cuba, Brazil, and the southern states of North America, with the same and allied genera in Ceylon. _Antennaria_ and _Pisomyxa_ seem to reach their highest development in hot countries.
The _Ascomycetes_ are represented everywhere, and although certain groups are more tropical than others, they are represented in all collections. The fleshy forms are most prolific in temperate countries, and only a few species of _Peziza_ affect the tropics, yet in elevated districts of hot countries, such as the Himalayas of India, _Peziza_, _Morchella_, and _Geoglossum_ are found. Two or three species of _Morchella_ are found in Kashmir, and at least one or two in Java, where they are used as food. The genus _Cyttaria_ is confined to the southern parts of South America and Tasmania. The United States equal if they do not exceed European states in the number of species of the _Discomycetes_. The _Phacidiacei_ are not confined to temperate regions, but are more rare elsewhere. _Cordierites_ and _Acroseyphus_ (?) are tropical genera, the former extending upwards far into the temperate zone, as _Hysterium_ and _Rhytisma_ descend into the tropics. Amongst the _Sphæriacei_, _Xylaria_ and _Hypoxylon_ are well represented in the tropics, such species as _Xylaria hypoxylon_ and _Xylaria corniformis_ being widely diffused. In West Africa an American species of _Hypoxylon_ is amongst the very few specimens that have ever reached us from the Congo, whilst _H. concentricum_ and _Ustulina vulgaris_ seem to be almost cosmopolitan. _Torrubia_ and _Nectria_ extend into the tropics, but are more plentiful in temperate and sub-tropical countries. _Dothidea_ is well represented in the tropics, whilst of the species of _Sphæria_ proper, only the more prominent have probably been secured by collectors; hence the _Superficiales_ section is better represented than the _Obtectæ_, and the tropical representatives of foliicolous species are but few. _Asterina_, _Micropeltis_, and _Pemphidium_ are more sub-tropical than temperate forms. The _Perisporiacei_ are represented almost everywhere; although species of _Erysiphe_ are confined to temperate regions, the genus _Meliola_ occupies its place in warmer climes. Finally, the _Tuberacei_, which are subterranean in their habits, are limited in distribution, being confined to the temperate zone, never extending far into the cold, and but poorly represented out of Europe. One species of _Mylitta_ occurs in Australia, another in China, and another in the Neilgherries of India; the genus _Paurocotylis_ is found in New Zealand and Ceylon. It is said that a species of _Tuber_ is found in Himalayan regions, but in the United States, as well as in Northern Europe, the _Tuberacei_ are rare.