SOUTH AFRICAN HEPATlC.^i <JR LU'ERWORTS. 



By TiKXMAs R()i!Er<TS(»i\ Sim. F.R.I I. S. 



The most interesting and the most neglected group of plants 

 in the African fiora is the HepaticcC. 



The members of this group are those cellular plants which, 

 together with the mosses, constitute the Bryophyta. 



They are distinguished from the mosses by having either 

 spiral elaters or sterile cells present among the spores in the 

 capsule ( except Ricciace^e ) , and by having onl\' unicellular 

 ihizoids, whereas those of the mosses are many-celled; also by 

 the more delicately cellular nature of their formation, the h}'aline 

 and evanescent seta of the ca])sule, and the formation and 

 dehiscence of the capsule itself. 



Many of them have lobed leaves, some have conduplicate 

 leaves, many produce folioles ( ami)higastria ) , and some are 

 entirely thalloid, all of which are characters unknown among 

 the mosses ; while the usually bilateral arrangement of the leaves, 

 when leaves are present, and the laxly hexagonal areolation, are 

 not common among the mosses. 



The sexual arrangements are, however, on the same general 

 lines as those of the mosses, and the alternation of generations 

 is similar, and the power of nonsexual reproduction by means 

 of gemniie occurs in both, hence the inclusion of both groups 

 in the one class Bryophyta, the Hepatica? being regarded as the 

 lower and the Musci as the higher group. 



The FTepatic.-ie are of no economic value, and even in the 

 economy of Nature they hold a very unimjjortant position. 



Most of the species are hygrophilous, inhabiting humid 

 forest situations, or the banks of streams, or stones in streams, 

 in .some cases under frecpient ir.'undation or constant s])ray. 

 Each species has its own kind of hal)itat, to wliich it adheres 

 more or less closely. 



But some species, especiall) in viev/ of their loosely cellular 

 structure, exhibit an extraordinary power of endurance against 

 drought, and habitually occur in sites which are practically 

 dust-dr\' for many months, where they drag out a flaccid exis- 

 tence during drought, and become fresh and vigorous again as 

 soon as moisture is available. These are, indeed, quite xero- 

 phytic species, 



Cithers, especially thalloid forms, under similar dr}- condi- 

 tions become more coriaceous in texture, and more or less pro- 

 tected bv scales, while in most of the hepatics the protection of 

 the growing point is highly specialised. 



The hygrophilous ty])e is probabl}- the older and more 

 normal, the xerophytic types being special adaptations to local 

 circumstances. 



The South African specie.-^, haA'ing to endure extreme 

 drought for manv montlis (sometimes vearsV even inside the 



