43^ SOUTH AFRICAN HEPATICE. 



South African genera are widely distributed in similar climates; 

 also that nn)St of the genera found in similar climates elsewhere 

 are represented in South Africa, though there are a few excep- 

 tions both ways, mostl}- in exceedingly local or monotypic genera. 



There are tropical genera which have not yet been recorded, 

 but our tropical regions have not yet been well explored in this 

 connection. There is also a scarcity of certain conduplicate- 

 leaved cold-region forms ( Scai)ania. Lophozia, etc.), which may 

 also to some extent be removed when the mountain streams of 

 the Drakensberg are further explored. 



Btvt there is no distinctively South African group, such as 

 occurs among the Phanerogams ( Protea, Restio. Erica, Mezem- 

 bryanthemum, etc.), the nearest approach being the tendency 

 toward a succulent sporogonium found in several genera ; also 

 the 2/ species of Lejeuneaceae may be compared with the absence 

 of that Family California.* 



In regard to the (listributi(jn of genera, one has to consider 

 along with that the limitations of these genera, on which point 

 ©pinions still vary considerably, antl may do so for ages. 



But in regard to species, although many are of wide range, 

 a very considerable number of the names on the list rejM-esent 

 what are regarded as South African endemic species, though 

 closeb' related and sometimes almost identical with species 

 which occur elsewdiere. 



On this point Spruce, after describing minute characters 

 wherein one South African plant differs from its European 

 relative, very appropriately says: "Now the question is, are 

 these differences to be accounted specific or merely varietal? 

 The same question recurs almost whenever a European species 

 reajjpears in South America and Africa, for the coincidence of 

 structure is scarcel}- ever exact, and although we are sure that 

 these analogous forms have had a common ancestor at no very 

 remote period, we find it difiicult to so bridge over the oceanic 

 interval as to account for the very wide dispersion."! 



C. F. Austin, in dealing with the forms of a certain moss, 

 says : " These forms clearly depend upon external causes — as 

 matrix and climate — for the development of their peculiarities ; 

 fn fact, so far as I have observed, there is no sitcJi thing as variety 

 among any of the Cryptogams in the sense in which the term 

 variety is applied to Phanerogams ; none of them having the 

 power to rei:)roduce their peculiarities under a change of matrix, 

 or of climatic influence." + 



T^articularly in regard to colour and vigour, on which many 

 .so-called species have been founded, does this hold good. If 

 Austin's view is accepted, then we have local conditional forms. 

 subject to circumstances which may or may not be of a per- 



* •' The Hepaticse and Anthocerotes of California." by M. A. Howe. 

 rSgg. 



t Spruce, in Pearson, Hepaticcc Xatalensis. (1886) 10. 

 i Bot. Cazcttc. October 1877. page 14.3- 



