in 



CONTENTS. 



PAGE 



Introduction I 



Geographical Characteristics of Algeria 2 



Climate of Algeria 6 



Some Characteristics of the Vegetation of the Tell 15 



The Forests of Algeria 18 



The High Plateau 20 



Boghari to Laghouat 20 



Djelfa to Laghouat 22 



Laghouat 23 



The Oasis of Laghouat 24 



The Plain 25 



The Dunes near Laghouat 27 



The Mountains about Laghouat 28 



Effects of Grazing on Vegetation near Laghouat 29 



From Laghouat to Ghardaia 31 



Region of the Dayas 31 



Daj^a of Tilrempt 32 



The Chebka 34 



Ghardaia 36 



The Oasis of Ghardaia 38 



The Plain (Hamada) of Ghardaia 39 



The Mountains about Ghardaia 41 



The Valley of the M'Zab 41 



Protected Areas near Ghardaia 42 



Root-Habits in the Ghardaia Region 44 



Leaf-Habits in the Ghardaia Region 49 



Growth and Flowering Habits in the Ghardaia Region 49 



Ghardaia to Touggourt 50 



Ghardaia to Ouargla — Vegetation 53 



Ouargla to Touggourt — Vegetation 56 



Touggourt to Biskra — Physical Features and Vegetation 58 



The Biskra Region 59 



Topography 59 



Plant Habitats of the Biskra Region 60 



Vegetation of the Biskra Region 61 



General Summary and Conclusions 66 



The Environmental Conditions of Plants in Arid Regions 66 



Environmental Features of the Flora of Algeria 69 



Some Effects of Temperature and Rainfall in Southern Algeria 71 



The Soil Relation in Southern Algeria 73 



Root-Characters and Species Distribution in Southern Algeria 76 



The Biotic Factor • . 77 



Comparison of Some General Features of the Vegetation of Southern Algeria 



and of Southern Arizona 79 



iii 



