S.A. I'.KVOl'll N TA. 403 



some arc considcrabU restricted iby their water re(juireineiu. 

 Genera wlricli j)ermanently inhabit the drier rock surfaces in- 

 clude : — 



Audrccca. CaiHpylof>iis, Polytr'uli 11 111, 



Rhacomltrium, Bryiim { aiyciifntiii ) , Ptyclwuiifriiini . 



Gnmniia, Zygodon, 



while somew hat nioister rock margins have also : — 



Bartramidula, Aongstrivinia, Bryum alpinum, 



Pogonatitm. Scelania, Bryitjii afro-alpiinnii. 



D if rich II HI, Trcinaiudon^ etc. 



a truly wonderful mixture sometimes lveint{ found on our 

 frequently snow-clad mountain summits of sj^ecies separately 

 re]>resenting the hig^hest UKamtain tyi)es of luiro])e. Asia. NorMi 

 Y^merica, South j\inerica, New Zealand. Tristan d'Acunha. 

 Abyssinia, and Central Africa, all healthy and \igorous <'n\ 

 these respective mountain -summits, though al)>e!U or almost 

 absent elsewhere. 



(iKNEKAi- Conclusion s. 

 What has 'oeen said leads us to these general conc".u>iun^ : — 

 South Africa is rich in >i.ecies of Bryophyta. many endemic; 

 biU i)oor in endemic genera. 



South Afr"ca appears lo be ihc conimcn meetiTig-grounci 

 of Northern tyi)es. Southern types, and another diagonal tyjx;-. 

 in additi<m to whatever may belong to Africa and its islands, or 

 be endemic t<j South Africa. 



This common meeting-ground is \ cry })roi)ounced, and \er\ 

 remarkable among the comparati\'ely few species inhal)iti']ig tlu 

 mountain sunmiits. 



These facts indicate jirobable former land connections wher^- 

 no such c<^nnections have existed for a very long time past, thai 

 long period accounting for s])ecific variation after the generic 

 characters of the mosses and the main divisions of the Hepatica- 

 had become fairly well fixed- 



The aggressic)n of climatic conditions, regulated by the hugi 

 more or less arid area, over tlie smaller and retrogressive humid 

 area.s. accounts ifor the wide distriibution in suitable but aiow 

 seiparated sjjots. of many cosmopolitan and other species, which 

 are unable to survive in the arid or semi-arid inter\ening and 

 adjoining tracts. The I'Lastern Region. conse(|Uently. has a rich 

 and varied bryojihytic flora. 



( )ai account of aridity iJr^ophyta are few. scarce and 

 peculiar west of the main escarpment. 



'l"ro])ical conditions bring tropical species as far south a- 

 these conditions extend. 



The S<mth-\\'est region is more specialized than tlu 

 others, a- also i^ the case in regard to its higher flora, indical- 



