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800 MB. J. ball's spicilegitjm tlok^ maroccan^. 



bourhood of Tangier and Tetuan, and are not seen in the central 

 or sonthern provinces of Marocco. 



The Algerian flora, so far as it offers special characteristics to 

 distinguish it from the general Mediterranean type, owes its in- 

 dividuality mainly to species endemic in the mountain region of 

 the Lesser Atlas, or on the high plateaux that present such a pecu- 

 liar feature in the geography of Southern Algeria. 



It is highly probable that most of these extend into Eastern and 

 Central Marocco ; but in the limited region known to us these cha- 

 racteristic species of the Algerian flora are for the most part 

 wanting, and even in the Great Atlas but a small number of them "^| 



have yet been seen. f 



Although several of the species characteristic of the Desert 

 flora extend beyond their original boundary, and a few of them 

 are found even in the south-east of Spain, there are few better- 

 marked botanical provinces than that of the desert regions of 

 Western Asia and Northern Africa. Considering the wide portion of 

 the earth's surface occupied by tbe hot stony or sandy plains that 

 extend with unimportant interruptions nearly from the banks of the 

 Lower Indus to the Atlantic coast of Southern Marocco, the gene- 

 ral uniformity of its scanty vegetable population is a fact very re- 

 markable in botanical geography. Unfortunately our knowledge 

 of the true desert-region of Southern Marocco, namely that which 

 extends along the Southern side of the Great Atlas chain, is ex- 

 tremely limited ; but when the collections recently received by 

 M. Cosson from his collector are fully enumerated, it will be seen 

 that many species of this peculiar type extend to within a few 

 leagues of the Atlantic coast. But even in the low country, 

 on the northern side of the Great Atlas, traversed by us there are 

 some considerable tracts closely approximating in their physical 

 conditions to the northern skirts of the Sahara. Many of the 

 characteristic desert-species there reappear, although they are 

 separated by lofty mountain-ranges from what may be considered 

 their natural home. 



The least-important element that goes to make up the Marocco 

 flora, if we measure it by the number of representative species, 

 but in some respects one of the most interesting, is that revealed 

 by the presence of a small number of species common to the Ma- f 



roccan and the Macaronesian * floras. Of these all but one are d 



* I have ventured to use the name Macaronesia in a rather wider sense than , 



?ome preceding writers, including under it Madeira with its dependent islets, 



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