312 



FUNGI 



less detail under the different groups of fungi. It may be well to note 

 that transition-forms occur between the simple and compound types of 



^k 





FiG. 273. — Agitricus dryophilus Bull, a, compound sporophore, longitudinal section showing 

 the course of the hyphse, a very youn? complete specimen i'3 mm. in height, first begiiinings 

 of pileus : b, older specimen with pileus 2*5 mm. in breadth : /, piece of a lamella (slightly 

 magnified). (After de Bary.) 



sporophore : for example, Penicillium, though commonly simple, some- 

 times produces tufts of sporophores formerly supposed to belong to a 

 different fungus under the generic name of Coremium. 



Spores. 



The prevailing mode of spore-formation is by acrogenous adjunction. 

 The terminal portion of the mother-cell or a special protuberance formed 

 on it is cut off by a transverse wall, and this daughter-cell then drops off 

 as a spore. The basidiospores of Basidiomycetes may be taken as an, 

 example. Finely pointed processes are formed on the summit of the 

 basid, and these swell into ball-like form at the apex. The globular 

 body is then abjointed and set free as a spore. Series or chains of 

 spores are successively formed in like fashion in Cystopus, Penicillium, 

 Uredinese, &c. Spores are also endogenously formed within mother- 

 cells — sporanges — and these are of two kinds, motile and non-motile. 

 Examples of non-motile spores thus formed are to be found in Mucor, 

 and in the ascospores of Ascomycetes. Such spores are either set free by 

 the disappearance of the sporangial wall or by internal causes effecting 

 their ejection. Motile spores or zoospores (swarm-spores) possess the 

 power of moving freely in water by means of fine whip-lashes or cilia, 

 and examples of these are to be found in the Saprolegniese and Perono- 

 sporese, the groups presumably most nearly related to Algae. That the 

 phenomenon of the production of swarm-spores is one nearly akin to that 



