353 



to the bed of the Khan river west of Usakos conveys the 

 impression that the vegetation of the transition zone passed 

 through by the former route is more luxuriant and richer in 

 species than the corresponding flora on the west of the Khan. 

 If this is generally true it is no doubt to be explained by the latter 

 district being nearer to the sea. The conclusion that the Rossing- 

 Usakos flora is merely a westerly extension of the same transition 

 zone seen to the east of the Khan rests upon (1) the dominant 

 position of the Euphorbia, (2) the increasing proportion of the 

 grasses from south to north, (3) the gradual assumption of 

 the " Acacia-scrub " character owing to the appearance of species 

 not met with to the south and west, (-1) the persistence of several 

 characteristic Namib plants especially Commiphora saxicola ; the 

 acaulesent Aloe ; Blepharis sp. ; and the Gleome. 



The essential elements of the Acacia formation, which extends 

 from Usakos and Karibib as far as the most easterly point reached 

 in this journey, can be seen as the train descends to the Khan 

 bed. In the bed of the river we see a flora identical, as to its 

 principal constituents, with that which flourishes in the Bwakop 

 river bed at Haikamchab, 100km. to the south-west, but including 

 species not seen elsewhere. The following plants, already met 



with at Haikamchab, were recognised i — Acacia albida, A.giraffae 



(doubtfully), Euclea pseudebenus, whose habit so strongly suggest* 

 the Weeping Willow, Oaroxylon sp., the white-flowered Gleome, 

 and Tamarix articulata ; a small Sarcostemma is possibly 

 identical with that found some 300 feet above the Swakop at 

 Haikamchab (S. viminale). Two other species of Acacia were 

 noted and there were many other unrecognised shrubs and 

 herbaceous plants. 



For several miles as we approached the Khan we passed con- 

 tinuously through an enormous swarm of large locusts flying in 

 a general westerly or north-westerly direction. They were 

 accompanied by hundreds of large birds, obviously locust-eaters, 

 locally designated as the " locust-bustard," which in these parts 

 are only seen with the locusts. 



The Acacia Park Forest. 



Usakos has the appearance of a thriving little town in the 

 construction of which wood plays a more important part tnan in 

 settlements nearer the coast, The Otavi Company has e sta bl si iea 

 extensive railway works here. Its situation is in a ™Uej lead ng 

 down to the Khan, almost enclosed on three sides by ^\; ™ un ^ 

 hills clothed to tile summits with an Acacia 'park forest ana 

 an undergrowth of shrubs and grasses. The ^pressmn g u n 

 b very pleasing, partly due, no doubt, to the strong ^con^st 

 between the green luxuriance of early summer and the J eLow 

 bareness of the Namib through which we b^e recently passed 

 No cattle were seen, but the country is doubtless capable ot 

 supporting them in large numbers. 



Flora.-Of the flora between Usakos ^d Wmdhuk w^ich 

 appears to find the most favourable conditions for ^ 8 ^nHon 

 in the neighbourhood of Okahandya, the ^.^^^ 

 stituents are the Acacias. Everywhere the predominant species 



