THE PLANT ECOLOGY OF THE COAST BELT OF NATAL. 897 



(b) Floating- Aquatics. — These occur in shallower 

 water. Aponogeton natalense and A. spathaceum 

 var. junceum are often dominant. Nynipha'M sp. (near 

 Madagascar en sis, fide Medley Wood) is another charac- 

 teristic species. Species of Utricularia are common, U. 

 foliosa, U. exoleta, U. stellaris, U. preliensilis,. 

 Jussiaea repens (J. fluitans), Limnanthemum in- 

 dicum (84), Ti'apa bispinosa, Lemna minor, L. gibba, 

 Wolffia denticulata also occur in this zone. 



(c) Phragmites or Reed Zone. — Phragmites com- 

 munis (PI. XXV, fig. 2) lines the river l)anks for long- 

 distances and forms often remarkabh* pure consocies,. 

 probably because the smaller aquatics cannot survive in 

 the dense shade. The reed zone is not so frequent in the 

 vleis, though it does occur. The Spanish Reed, A i- undo 

 donax, an introduced species, is found in jilnces. It grows 

 usually taller than' the Phragmites. 



(d) Phragmites — Typha Associes. — Typha capensis 

 is frequently associated with Phragmites, growing in 

 stagnant pools. 



(e) Semi-aquatics. — There are a large numl)er of species 

 which grow close to the margin of the open water. They 

 may be looked on as belonging to the Phragmites zone 

 but they are light-demanding species, which do not, to any 

 extent, actually mix with the Phragmites. Some of them, 

 especially the smaller Cyperacese, seem to be rather widely 

 adaptable, and grow also among the vlei grasses at a later 

 stage in the succession. Juncus lomatophyl lus often 

 forms consocies and is one of the commonest species in this 

 zone. Species of Xyris grow in small tufts — X. anceps, 

 X. umbilonis, X. natalensis. There are several semi- 

 aquatic Utricularias, U. tribracteata, U. sandersoni, 

 U. livida and sometimes U. prehensilis. The Eriocaulons 

 (E. dregei, E. ruhlandi and E. woodii) are common. 

 Other characteristic species are: Limosella aquatica, 

 Mentha aquatica, Ilysanthes riparia. Nasturtium 

 officinalis (probably introduced), Sium thuubergii,. 



