136 FUNGI. 



sion of sporidia by swelling tho gelatinous nucleus, it may 

 be assumed that this is one of the causes of expulsion, and 

 therefore of aids to dissemination. When Sphceriee 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 pro- 

 duction 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 SapralfgniacecB amongst the Physomycete*. 

 The zoospores being furnished with vibratile cilia, are for some 

 time active, and need only water in which to disseminate them- 

 selves, 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 com- 

 pelled 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.* 



* Corda, "Icones Fungorum," 6 vote. (1837-1842); Sturm, " Deutschlancls 

 Flora," Pilze (1841); Tulasne, " Selecta Fungorum Carpclogia;" Bischoff, 

 * Kryptogamenkunde " (1860) ; Corda, "Anleitung zum Sfcudium der Myko- 

 logie" (1842) ; Fresenius, "Beitrage zur Mykologie" (1850) ; Nees von Esen- 

 beck, " Das Sys'em der Pilze" (1816) ; Bonorden, "Handbuch der Allgemeinen 

 Mykologie " (1851). 



