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9 



THE VEGETATION OF THE HACKENSACK marsh: A TYPICAL AMERICAN FEN 



FENS OF AFRICA 

 Typical fen vegetation, with Phragmites communis prominent, is found 

 in Africa about Lake N'gami, at least 6 to 7 kilometers broad, and in Togo- 

 land, also about Lake Victoria Nyanza. The vleys of South Africa are char- 

 acterized by broad bands of Juncus maritimus, associated with the two South 

 African cattails, Typha australis and T. capensis, while Phragmites communis, 

 which plays a prominent role in other parts of Africa, is sparingly found, or 

 entirely replaced by Cladium Mariscus, associated with the calla-lily, Zante- 

 deschia cethiopica, which, with its white spathes, enlivens the South African 

 fenland in winter, while in summer water-lihes in flower are conspicuous in 

 the open places of the reed marshes. Vleys (Vleis) are fotind in South Africa, 

 according to Bews,* wherever a depression in the ground checks drainage, 

 such areas being known as "flushes." Few cover more than an area or two 

 of ground. The vegetation varies — (i) according to the amount of water 

 present, and (2) according to the degree of stagnation of the water. 



SUDD VEGETATION 



Much has been written about the vegetation of the marshes of the Upper 

 White Nile,t where vast masses of floating plants are moved hither and thither 

 and block the waterways by forming dams (Arab, "sudd") across them. The 

 mouth of the Bahr el Jebel, near Lake No and 627 miles above Khartoum, 

 may be taken as the northern gate of the Sudd region — a vast country of 

 marshes. The chief sudd-formers are Cyperus Papyrus, Panicum pyramidale, 

 Phragmites communis, Typha australis; between them, as floating plants, 

 occur the water-soldier, Pistia Stratiotes, Azolla nilotica, while the mass of 

 plants forming the Papyrus fringe are bound together by numerous twiners 

 and cHmbers. Toward Hillet en Nuer the banks are better defined and the 

 papyrus is replaced by Phragmites communis, while Panicum pyramidale, 

 called "Om-Suf," or "mother-of-wool," by the Arabs, on account of the 

 irritant hairs at the base of the leaves, has the faculty of growing both in 

 shallower and deeper water than the Papyrus, and not only occupies the land 

 which is uncovered at low Nile, but forms a fringe in front of the Papyrus in 

 the bed of the channel. 



* Bews, J. W.: The Vegetation of Natal. Annals of the Natal Museum, II, Pt. 3: 320, 

 May, 1912; Types of Vegetation in South Africa. Joum. of Ecol., IV: 147, Dec, 1916. 



t Brown, A. F.: Some notes on the "Sudd" Formation of the Upper Nile. Journ. Linn. Soc, 

 Botany, XXXVII: 51, 1904-1906. 



