CANNON 



PLATE 18 





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ft 



H^" 





v/ 



^v.-^ 



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Fig. 41. Habit of Salsola sp. (below), and Echinopsilon muricatus, from the M'Zab Valley, Ghardaia. 



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Fig. 42. Ghardaia to Ouargla. View overlooking the hamada about 28km. from Ghardaia. The relatively 



abundant vegetation is associated with a light cover of sand over the area shown. The leading 



species are Aristida, Deverra, and Haloxylon. 



