396 S.A. HRYOPHYTA. 



not difficult to explain, the climatic conditions being unfavotir- 

 bble. 



The latest and apparently the most satisfactory classifica- 

 tion is that given in Cavers' " Inter-relationship of the Bryo- 

 phyta " (1911). following which we find the representation tc 

 be: — 



I. Sph.erocarpales.— -Represented only by one species of 



Riella, only once seen. 



II. Marchantiales. — Well represented, but Monocleacese and 



Cleveaceie are absent. 



III. JuNGERMANNiALES. — Well represented, the most notable 

 feature being that the large family Scapaniaceae is repre- 

 sented b}' one species only, and that confined to the SAV. 

 region, so far as is known. 



IV. Anthocerotales. — Well represented by Anthoccros. Den- 

 droccros has not yet been found, though known from /Vfrica 

 and its islands. South America, and Australasia. Notothylas 

 and Mcgaccros are absent. 



V. Sphagnales. — Present but rare in the moister and fully 



exposed localities ; most frequent on Table . Mountain ; 

 absent ifrom the Karroo and from all forests. 



VI. Andre.1£.\le.s. — Represented by t)ne or two species, very 

 rare; found only on mountain rocks. 



\TI. Tetraphidales. — ^Absent from Africa; known only from 

 the Northern Hemisphere, New Zealand, and Samoa. 



VIII. Poia'TRICHALes. — Well represented, and through the 

 laminated leaves well suited for exposed ])Ut showery 

 localities. 



IX. BuxBAUMiALEs. — Abseut from Africa exce])t Madeira), 

 known o'nly from Northern Hemisphere and East Indies, 

 and one species in each of New Guinea, Tasmania, Peru. 

 South-Eastern' Brazil, and Viti Island. 



X. Eu-Brvales. — Well represented by most of the temperate 



and sub-tropical families. Some absentees have already been 

 referred to. Permanent marshes being almost absent, 

 swamp mosses are few, and through uai suitable climatic 

 conditions Splachnacea?e is almost absent. 



Ecology of South African Bryophyta. 



From the ecological standjx)int there is |)resent much of 

 great interest in the South African Bryophyta. The following 

 tyi^es occur: — 



I. Pioneer Species Colonizing New Ground. — Almost 

 all the Bryophyta may be ipioneers, but in difi'erent degrees, some 

 species, and especially under certain conditions, being the earliest 

 colonizing species of plants, while others may sometimes be so. 

 but probably more often follow blue-green Algse and Lichens 

 Intimately connected with the behaviour of each species in this 

 respect is the nature of the nidus required by its spores in order 

 to germinate aaid to develop into plants; in some (as in Funaria ) 



