CH. vri. NORTHEBN BASE OF THE ATLAP. 165 



stems die down nearly to the root every winter ; and our 

 belief that this was an entirely new species only yielded to 

 subsequent careful examination, which proved that it is no 

 other than Broussonnet's plant. 



The date-palm had disappeared soon after we entered 

 the hills ; here, and elsewhere on our route, it seems to be 

 confined to the lower region, rarely attaining the level of 

 3,000 feet above the sea. Its place was here supplied by 

 the palmetto [Chamcerops humilis), which seldom forms 

 a trunk, perhaps because it is not allowed to attain a 

 suflBcient age. As we advanced, the vegetation constantly 

 offered a more varied and attractive aspect ; and one of 

 our first prizes was a new species of thyme {Thymus 

 Tnaroccanus, Ball), somewhat like the species of the Argan 

 zone, but with oblong leaves and uncoloured bracts. Of 

 comparatively familiar forms there were Cistus monspe- 

 liensis, and C polymorphus, the first species of that 

 genus that we had seen in South Marocco, the pretty 

 little Gleonia lusitanica, with many other Labiate. Of 

 plants new to our eyes by far the most interesting was the 

 curious Polygala Balansce. To those who know only the 

 milkworts of Europe and North America, it must seem, 

 strange to hear of a large shrubby Polygala, with branches 

 that end in a sharp point, few small leaves, so quickly de- 

 ciduous that it generally appears quite leafless, and large 

 flowers of a showy purple-red colour. In truth, although 

 there is great variety of form in this large genus, the 

 species which is common throughout the lower valleys of 

 the Great Atlas is very distinct from all its congeners. 

 In Arabia and South Africa there are some species forming 

 dwarf bushes with spinescent branches, but in other re- 

 spects very different. When full grown this is six or eight 

 feet in height ; and the round, green, almost leafless stems 

 give it, when the flowers are absent, much the appear- 

 ance of Spartium junceum, the large broom of Southern 

 Europe. 



After riding some way up a rather steep stony track. 



