346 PLANTS, SEEDS, AND CURRENTS 



interesting question presents itself in connection with the sources of 

 the Peat-mosses and Carices of South Africa, since there are two 

 alternatives. Their ancestors may have come from the north, over- 

 land across the continent, or they may have traversed the Southern 

 Ocean in their passage from either the South American or the 

 Australian region. Here an appeal must be made to the connections 

 of species outside the continent. 



(A) The Carices. — In the case of Carex the question has been 

 already raised and answered with respect to four species, C. divisa, 

 vulpina, externa, and acutiformis, which are European species that 

 having reached North Africa extended their range to the southern 

 part of the continent, not one of them having been found either 

 in South America or in the Australian region. Neither of the two 

 other species concerned, C. cernua and C. cederi, gives a decisive reply. 

 Thus the first named is a wide-ranging species, which, in the form 

 of a fairly well- distributed special variety has obtained a slight 

 hold in Australia in a single locality in New South Wales, a some- 

 what better footing in New Caledonia, and a secure establishment 

 in South Africa. Here the indications are indeterminate; but the 

 scale turns against the trans- oceanic hypothesis, since it seems more 

 feasible that Asia served as the common focus of dispersal. The 

 testimony of the second species, C. cederi, is also uncertain. Found in 

 North America, Europe, and Asia, this Carex is represented by a 

 special variety, cataractaz, in different localities in South Chile and 

 Patagonia, in a single locality in South Africa (Basutoland), and in 

 various localities in Tasmania and in the Alps of New Zealand. Here 

 it would seem most likely that whilst South Africa derived the variety 

 across the ocean from Patagonia, the species reached Chile overland 

 from North America, and Tasmania from Central Asia, and that it 

 underwent the same varietal change in both those southern regions. 



The conclusions to be formed from the outside connections of the 

 six South African species of Carex here concerned, are that four only 

 could have been derived overland from Europe, that one of them 

 probably hailed across the South Atlantic from Patagonia, and that 

 the sixth was perhaps Asiatic in origin. On the whole, it would 

 appear that South Africa has mainly derived its Carices overland 

 from the northern hemisphere. 



(B) The Peat-mosses. — The South African Peat-mosses tell the 

 same story. Of the five species found outside the continent none 

 occur in either South America or in the Australian and New Zealand 

 region. Evidently South Africa has been stocked with its species 

 of Sphagnum from the north. Of these five species Madagascar 

 and the Mascarene Islands hold all. One of them, S. pappeanum, 

 which oceurs on the mountains of East Africa, as on Ruwenzori, 

 has a most remarkable distribution. Outside the continent it has 

 been recorded only from the islands of Teneriffe, Bourbon, Rodriguez, 

 and Amsterdam. 



The Mystery of Sphagnum pulchricoma. — Before quitting 

 this subject allusion should be made to the solitary Sphagnum con- 

 nection between the continent of Africa and the New World. This 

 is the more strange, since Africa, if we exclude the Mediterranean 



