putaminum_ the sporidia are extraordinarily large. [Illustration: FIG. 68.--Ascus and sporidia of _Hypocrea_.] [Illustration: FIG. 69.--Sporidium of _Sphæria ulnaspora_.] [Illustration: FIG. 70.--Sporidia of _Valsa profusa_ (Currey).] [Illustration: FIG. 71.--Sporidia of _Massaria foedans_. × 400.] [Illustration: FIG. 72.--Sporidium of _Melanconis bicornis_, Cooke.] [Illustration: FIG. 73.--Caudate sporidia of _Sphæria fimiseda_.] [Illustration: FIG. 74.--Sporidia of _Valsa thelebola_.] [Illustration: FIG. 75.--Sporidia of _Valsa taleola_. × 400.] [Illustration: FIG. 76.--Sporidium of _Sporormia intermedia_.] [Illustration: FIG. 77.--Asci and sporidia of _Sphæria_ (_Pleospora_) _herbarum_.] [Illustration: FIG. 78.--Sporidium of _Sphæria putaminum_. × 400.] The dissemination of the sporidia may, from identity of structure in the perithecium, be deemed to follow a like method in all. When mature, they are in a great measure expelled from the mouth of the perithecia, as is evident in species with large dark sporidia, such as exist in the genera _Hypoxylon_, _Melanconis_, and _Massaria_. In these genera the sporidia, on maturity, may be observed blackening the matrix round the mouths of the perithecia. As moisture has an evident effect in producing an expulsion of sporidia by swelling the gelatinous nucleus, it may be assumed that this is one of the causes of expulsion, and therefore of aids to dissemination. When _Sphæriæ_ are submitted to extra moisture, either by placing the twig which bears them on damp sand, or dipping one end in a vessel of water, the sporidia will exude and form a gelatinous bead at the orifice. There may be other methods, and possibly the successive production of new asci may also be one, and the increase in bulk by growth of the sporidia another; but of this the evidence is scanty. Finally, OOGONIA may be mentioned as occurring in such genera as _Peronospora_ amongst moulds, _Cystopus_ amongst Uredines, and the _Saprolegniaceæ_ amongst the _Physomycetes_. The zoospores being furnished with vibratile cilia, are for some time active, and need only water in which to disseminate themselves, and this is furnished by rain. We have briefly indicated the characteristics of some of the more important types of spores to be found in fungi, and some of the modes by which it is known, or presumed, that their dissemination takes place. In this summary we have been compelled to rest content with suggestions, since an exhaustive essay would have occupied considerable space. The variability in the fruit of fungi, in so far as we have failed to demonstrate, will be found exhibited in the illustrated works devoted more especially to the minute species.[F] [A] Cunningham, in "Ninth Annual Report of the Sanitary Commissioner with the Government of India." Calcutta, 1872. [B] See "Corda Icones," tab. 2. [C] Corda, "Icones Fungorum," vol. vi. Prague. [D] Tulasne, "Fungi Hypogæi." Paris.