=Germination of spores= (conidia and chlamydospores). In many spores may be found one or more _germ-pores_, _i.e._ thinner places, either in the inner membrane (uredospores, _Sordaria_) or in the external membrane (teleutospores in Rust-Fungi), through which the germination takes place. Generally this does not occur till the spores have been set free: in some Ascomycetes germination commences inside the ascus (_Taphrina_, _Sclerotinia_). The different ways in which the spores germinate may be classified into three groups. I. THE ORDINARY GERMINATION occurs by the spore emitting a germ-tube, which immediately developes into a mycelium. In spores with a double wall it is only the inner membrane which forms the germ-tube. In swarmspores a single wall is formed after the withdrawal of the cilia, and this, by direct elongation, becomes the germ-tube. The protoplasm accumulated in the spore enters the hypha, which, in pure water, can only grow as long as the reserve nourishment lasts. =2.= GERMINATION WITH PROMYCELIUM differs only by the circumstance that the hypha developed from the germ-tube has a very limited growth, and hence it does not immediately develope into a mycelium, but produces conidia (Rust-and Brand-Fungi). This promycelium must only be regarded as an advanced development of a conidiophore or basidium. =3.= THE YEAST-FORMATION of conidia consists in the production of outgrowths, very much constricted at their bases, from one or more places. Each of the conidia formed in this manner may again germinate in the same way. When sufficient nourishment is present, a branched chain of such conidia is formed, and these are finally detached from one another. Yeast-like buddings from the conidia are produced in various Fungi, _e.g. Ascoidea_, _Protomyces_, Ustilagineæ, Ascomycetes, Tremellaceæ, etc. In the Ustilagineæ these conidia are an important element in the development. The budding conidia of _Exobasidium_ forms a “mould” on the nutritive solution. The yeast-like conidia are not to be confounded with the “Mucor-yeast” (comp. Mucoraceæ). For _Saccharomyces_ see Appendix to the Fungi, page 176. In a compound spore (_i.e._ when a mass of spores are associated together) each spore germinates on its own account. There are sometimes, however, certain among them which do not germinate, but yield their contents to those which do. The _length of time_ for which conidia can retain their power of germination is shortest (being only a few weeks) in those having thin walls and containing a large supply of water (Peronosporaceæ, Uredinaceæ). In many spores a resting period is absolutely necessary before they are able to germinate (resting spores). It has been observed in some spores and conidia, that the faculty of germinating may be preserved for several years if the conditions necessary for germination remain absent (Ustilagineæ, _Eurotium_, _Penicillium_).