144 



assuming dominance. It is often difficult or impossible to 

 say whether the change is due to burning or to grazing, or 

 if to the latter, then whether the effect is directly the result 

 of Anihistiria being eaten out, or the result of changed soil 

 conditions. The only way in which 'he influence of the 

 various factors can be analysed is by a series of controlled 

 experiments on areas, where the vegetation has been carefully 

 mapped. A series of permanent quadrats should be set aside 

 and each should receive different treatment as regards burn- 

 ing, grazing, etc., one or more being left entirely untouched, 

 and this should be done for every different variety of grass- 

 land. kSome experiments of this nature are, I understand, 

 being carried out by the Union Department of Agriculture, 

 but of course several years must elapse before definite results 

 can be obtained. 



Hie feeding value of different types of grassland and grasses. 



To a large extent, this is hardly a botanical cpuestion, 

 since definite results can best be obtained bv feeding' tests, or 

 by chemical analyses, if they are made at different times, and 

 under varying conditions. The morphological appearance and 

 ecological behaviour of the grass often enable the botanist to 

 reach a conclusion regarding the probable value of a grass, 

 but such conclusions must always be accepted with caution. 

 Farmers also by continual observation of the kinds of grasses, 

 that are most eaten, and the results, have reached conclusions, 

 and in the course of my many botanical explorations, I have 

 endeavoured to find out what those conclusions are. Wherever 

 I have found a fair consensus of opinion I have noted it under 

 each species dealt with in Part ill. In other cases I must 

 confess that oj)inions were too contradictory to be worthy of 

 any attention. 



The results for different types of grassland may be sum- 

 marized as follows : — 



1. The ruderal or land grasses which grow often with 

 Mealie and other crops as weeds, and soon become plentiful 

 or completely dominant in waste cultivated land, are on the 

 whole rather good grasses, and some of them may be classed 

 as very good, e.g.., the Digitari'as, Panicums, Eleusines, and 

 species of Chloris. Cynodon dactylon, which is often ruderal 

 or a pioneer along pathways and on bare spaces, or old cattle 

 kraals, etc., is also a good grass. Tricholaena rosea is not 

 much valued here, though its seeds have been exported, and 



