CANNON 



Fig. 75. Detail of square No. 2, near area shown in fig. 74. Ferula and Haloxylon are the leading species. 



Fig. 76. Root-habit of Haloxylon scopariurn, 

 from a wash near Biskra. 



3*51 



A 



$£ 



-7 " 



Fig. 77. Young shoots and mature roots of Ferula vesceritensis. 



North of Biskra. 



