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On the great sandy plains from South. West Africa and 

 Namaqualand through Calvinia, Gordonia, and Prieska the 

 Toa grass A. hrevifolia a very xerophytic, suffrutescent species, 

 covers great areas. Other important semi-desert species of 

 the West are A. ciliata, A. obtusa, A. namaquensis, A. sahuli- 

 cola, A. uniplumis, A. dregeana, A. hochstetteriana, A. suha- 

 caiilis. The only characteristic species in the Cape region is 

 A. capensis. In the Karroo, and in the transitional belt 

 between Karroo and Eastern Grassveld Aristida remains the 

 most important genus, the chief species being A. congesta 

 (Steek gras), A. vestita, A. barbicollis, A. adscensionis, A. 

 bipartita, A. stipoides var. meridionalis , A. ciliata, A. 

 proxima, A. obtusa, A. uniplumis. 



In Eastern grassland Aristida consocies are widespread 

 in the initial stages of the prisere, the chief species being 

 A. junciformis, A. angustata, A. congesta, A. barbicollis, 

 A. bipartita, A. aequiglumis, A. sericans, A. spectabilis. 

 Through the influence of grass-burning, and over-stocking, 

 Aristida consocies become semi-stable, and often replace 

 climax Anthistiria or Andropogon consociations, forming 

 what W. G. Smith has called "substituted types." -, They 

 really represent initial or primitive stages of the succession. 



The species of Aristida are all xerophytic, the semi-desert 

 types extremly so. They have strong, deep roots, and hard, 

 wiry culms. The name "wire grass" is applied to several of 

 them (e.g., A. junciformis and A. barbicollis) in the same 

 way as the native name "umgongoni." Their leaves are 

 narrow, usually convolute, and very hard. Their fruits 

 ("seeds") are capable of hygroscopic movements. If they are 

 placed on the surface of moist soil they will soon be found 

 to have buried themselves. Some of the seeds, e.g., those of 

 A. congesta (Steek grass) bore their way even through the 

 skin of sheep. All this is of importance as showing how they 

 are fitted to act as pioneers, and colonize bare areas. The 

 species usually grow in dense caespitose tufts which give 

 shelter, and a certain amount of shade for the seedlings of less 

 resistant species like Anthistiria, which usually comes up 

 through the midst of the clumps. The anatomy of the leaf 

 of A. bipartita is shown in Fig 6. The ridges in this case are 

 prominent, with motor cells between them. The leaf folds 

 in dry weather, and there are hairs on the upper surface. The 

 bundles are not girdered, bat there is a thick continuous band 

 of sclerenchvma along the lower side, and across each of the 

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