BOOKS AND CURRENT LITERATURE 



Botanical Featuees of the Sahara. — Cannon has published an 

 amply illustrated account of the geography and vegetation of the 

 Algerian Sahara/ instituting comparisons of that region with the 

 deserts of the United States. His route lay southward from Algiers 

 across the Tellian Atlas and Saharan Atlas mountains, and the pla- 

 teau by which they are joined, and then south-eastward over the 

 Saharan desert to Ghardaia and Ouargla. The Tellian Atlas bears 

 forests of pine (Pinus halepensis) , cork oak {Quercus suher), and juniper 

 {Juniperus oxycedrus and J. phoem'cea) with cedar {Cedrus atlantita) 

 at the highest elevations. The Saharan Atlas, which lies further 

 from the Mediterranean, is more lightly forested with the same species 

 of trees. The intermontane plateau is largely occupied by saline de- 

 pressions and possesses a scant vegetation. 



To the southward of Laghouat lies the Sahara, with its monotonous 

 topography: alternating flat stony areas, rolling sandy areas or dunes, 

 and occasional depressions which offer more favorable soil moisture 

 conditions. Some of the depressions are highly saline (chotts), while 

 others possess good agricultural soil (dayas). 



The dunes present a very scant vegetation (Aristida, Tamarix, Re- 

 tama, Acarithyllis, et al.), while the plant cover of the stony plains 

 ma.y be extremely light or may consist of considerable numbers of 

 plants, mostly small in size. No trees are found outside the dayas 

 and oases, and the only conspicuous plants of the plains are: Haloxylon, 

 Zizyphus, Ferula, Zollikoferia, Deverra, Ephedra and Aristida. Ephem- 

 eral herbaceous plants are also found in some places on the stony 

 desert plains. 



In the dayas the pistache tree (Pistacia atlantica) is found at cer- 

 tain localities, and there is a relatively abundant vegetation, including 

 Pegafium, Retama, Henophyton, Capparis and Zizyphus. The chotts 

 are without vegetation in their most alkaline portions, but Nolletia, 

 Halocnemon and other shrubs are abundant about their edges. 



The author has described some of the climatic conditions of the 

 regions visited. The rainfall decreases from 19.8 cm. (7.79 in.) at 



1 Cannon, W. A., Botanical Features of the Algerian Sahara. Carnegie Inst. 

 Wash. Piibl. 178. Pp. 81, pis. 36. Washington, 1913. 



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