iUS 



present tlie soil, whicli is a hard-baked clay, with a little sand 

 on the surface, is hardly the type which would support Anthis- 

 tiria Veld. 



The explanation of the change, which is here suggested, 

 is ^s follows. "When the district became opened up to the 

 white settler, sheep and other stock were introduced, and the" 

 Veld grasses were regularly burnt. Anthistiria is a species 

 with its innovation buds intravaginal, and it does not stand 

 burning well. If the burning is done early, it is not alllowed 

 to seed, and, even if it were, the seeds seem to prefer to ger- 

 minate in the shade of dead herbage, through which the seed- 

 lings may be seen to make their way. Anthistiria rarely 

 colonizes bare areas. Stock prefer it to most other grasses, 

 and it tends to be eaten out. Its gradual disappearance is a 

 common phenomenon on farms throughout the Eastern Grass- 

 veld region. Usually, however, it is replaced by initial stages 

 of the sere, chiefly worthless Aristidas, and not by a succulent 

 dwarf type like Danthonia, which, it may be recalled, is alsc; 

 eaten by sheep. We have not, however, exhausted the factors. 

 The constant tramping of the' soil by stock, when allowed to 

 wander to and fro at will, has a much greater effect on the 

 soil than is generally realized. The surface few inches are 

 hardened, and the rainwater, instead of soaking in, tends to 

 run off. Sheep tracks and cattle tracks serve as surface drains, 

 and these are very quickly deepened into dongas. The result 

 of it is that the whole of the soil is dried out by the system 

 of intersecting dongas, and only xerophytic grasses are able 

 to survive. It is a fortunate thing that a grass can sometimes 

 be xerophytic, and at the same time fairly nutritious, as is 

 the case with Danthonia purpurea, but it is very restricted 

 in its distribution, and its place is often, in fact usually, taken 

 by Aristidas or Eragrostis species, most of which are very 

 poor fodder grasses. The soil over which Danthonia is 

 dominant appears as dry as most Karroo soils, and another 

 economic aspect of the study appears worth investigating, 

 namely, whether Danthonia pvrfvrea would survive, under 

 Karroo conditions, and if so wli ether it would prove a better 

 food for stock than the shrubs at present dominant there. It 

 may be recalled tbat Danthonia penicilJata and D. rohusta, 

 according to Maiden, are two of the best fodder grasses in 

 Australia. 



One other point of purely scientific interest is the fact 

 that Danthonia purpurea, which has thus conquered for itself 

 a place in Eastern Grassveld, and ousted the sub-tropical 



