CARPOSPOREM. 
spring and form promycelia, from the sporidia of which the myceUa which bear the 
secidium-fruits are developed. 
On comparing this second case with the first it becomes evident that here 
several generations of mycelia are intercalated between the formation of the secidio- 
spores and the formation of the promycelium. These generations give rise to 
pecuHar reproductive cells, the uredospores and the teleutospores. 
A sexual act has not as yet been observed even in these well-known forms of 
^Ecidiomycetes. If, however, we adhere to the rule that in the Thallophytes, as in 
Cryptogams generally, the most complex form of development is the result of a 
sexual act, and if we assume that an act of this kind does actually take place in this 
case, we cannot but regard the aecidium-fruit as the sexually-produced generation \ 
The secidium-fruit will then correspond to the fructification of the Ascomycetes, the 
aecidiospores to the ascospores, and the uredospores, teleutospores, and sporidia to 
various forms of conidia. Should these probable assumptions be substantiated by 
future discoveries, it becomes at once evident that the nomenclature of the genera 
must be based not upon the forms bearing teleutospores, but upon those bearing 
secidia, for instance the genus now known as Puccinia will have to be feconstituted 
under the name of JEcidiufji, the genus Gymnosporangium under that of Roes leh'a'^ Sec, 
just as among the Ascomycetes not the conidia but the sporocarps afi'ord the basis 
for their systematic arrangement. 
That the uredospores and teleutospores are merely forms of conidia is demon- 
strated by the fact that they are present in some genera and species and absent in 
others, resembling in this respect the conidia of the Ascomycetes. They are both 
absent in Endophyllum, the uredospores are absent in Roestelia, and both are present 
in Vadium Berber idis and in JEcidium Legufninosarnm. 
The view which is here maintained is exclusively founded upon the well-known 
forms. There remains a much larger number of forms of which the life-history is 
only imperfectly traced. In a series of forms, for instance, the aecidium-fruits only 
are known [jEcidiu??! elatmum, Pint, abietiniwi^ , &c.), and it is still uncertain whether 
or not they reproduce themselves by the aecidiospores alone : in others only the 
teleutospores are known {Chrysomyxa, Puccinia Dianlhi, cojiipactd) : in others again 
only the uredospores {Cceoma pinitorquuni)-. uredospores and teleutospores, without 
secidium-fruits, are known in Melampsora and Coleosporium. The last-named cases 
recall Penicillium and Euroiium in which, formerly, only the conidia were known 
and not the true fructifications, but they difi"er from them in that they possess two 
kinds of conidia. It appears that, like Penicillium and other Ascomycetes, certain 
^cidiomycetes can reproduce themselves for many generations solely by means of 
their conidia (uredospores and teleutospores) without attaining the completion of 
their development in the formation of a true fructification (aecidium). 
The formation of the fructification of the JEcidiomycetes, like that of many 
Ascomycetes, is accompanied by the development of peculiar receptacles, the 
^ To this view I drew attention in the first edition of this book (1868). Oersted, loc. cit., and 
Brefeld also support it, [See also Stahl, Bot. Zeitg, 1874.] 
2 [The life-history of Mc. abietinum has since been traced by De Bary (Bot. Zeitg. 1879). The 
mycelium bearing uredo- and teleutospores infests the leaves of Rhododendron fermghienm and 
hirsuäim.'] 
