502 ZONES AND REGIONS [Pt. Ill, Sect. II 



' But this grassy tract is more remarkable for its woody plants than for its 

 humbler components. The woody plants are scattered singly or in groups over 

 the surface, and their dark foliage contrasts strikingly with the lighter green or 

 faded straw-yellow of the sward : they may be compared with the mezquit bushes 

 of the southern prairies, for, as on the prairie, the Mimosa-form chiefly predomi- 

 nates as a characteristic feature, while the remaining species may almost without 

 exception be regarded as fugitives from the riparian thickets. The social karroo- 

 thorn (Acacia horrida), a species of Acacia which is distributed throughout the whole 

 colony and has stiff ivory-white thorns and yellow fragrant capitula, here, as in the 

 dry river-beds of the Karroo, sometimes attains to tree-growth and then resembles 

 a stone-pine with its umbrella-shaped crown. No plant is more characteristic of 

 the grassy areas than this. Wherever the eyes of the traveller may turn, they 

 encounter the finely divided pinnate leaves of this Acacia. Its but slightly shady 

 crown is often traversed by climbing plants of the convolvulus-form, or covered 

 with woody parasites (Loranthus Dregei). . . . Other shrubs also, such as the ubi- 

 quitous Grewia occidentalis belonging to the Tiliaceae, the periodically deciduous 

 buffalo-thorn (Zizyphus mucronata), some species of Royena, a strongly aromatic 

 verbenaceous plant (Lippia asperifolia), and many others, are often found accom- 

 panying the thorn-bushes.' 



Northwards, on approaching the Tropic of Cancer, the trees of the savannah 

 become taller and their character quite decidedly tropical (Fig. 264). On the other 

 hand, the plateau of the South African colonies that extends to the west of Natal is 

 almost pure grassland (Fig. 265), except near the water-courses. In a westerly 

 direction dwarf trees and shrubs become more frequent (Fig. 266), the grass vege- 

 tation more stunted and drier, and the general character like a semi-desert. 



iii. GRASSLAND IN SOUTH AMERICA: PAMPAS. 



The pampas of the Argentine province Santa Fe have been described as 

 follows by Lorentz * : — 



'The description of the pampas, which we are accustomed to hear at home and in 

 which they figure to our fancy as absolute level plains with a horizon like that of 

 the sea, and in which for hundreds of miles not the slightest rising in the ground is 

 noticeable, is incorrect for the northern pampas ; it is truer of the pampas in the 

 north of the province of Buenos Ay res. The land of the northern pampas is slightly 

 undulating, and although to the eye the elevations and depressions are not imposing, 

 yet they may be at once perceived from the differences in the vegetation, and, for 

 a thousand practical reasons, they are of the greatest importance to the inhabitants 

 of the pampas ; above all to the European immigrant, who directs his attention 

 more to the cultivation of crops than to breeding cattle. . . . The cultivators' settle- 

 ments are dotted about on the canadas, the slight depressions where lagoons 

 frequently afford the needful supply of water for cattle and men, or at any rate 

 water occurs at a slight depth below the surface; where nature denotes by the 

 thick soft turf mixed with leaves that the conditions are specially favourable for 

 vegetation, and where cultivated plants find an ampler and steadier water-supply, 



1 Lorentz, op. cit., I, p. 17. 



