Manchester Memoirs, Vol. Ixii. (1918), No. 8. 7 



shows its graceful drooping shoots and Sonchus spinosus suggests a 

 tangle of barbed wire. It has no foliage leaves after the seedling 

 stage and is often spun up by Cuscuta. Citrullus colocynthus, with 

 its gourds the size of oranges, straggles over the heated surface of this 

 miniature Sahara. Of the leafy arborescent species of Euphorbia, 

 E. regis-Jubce and E. balsamifera are highly characteristic of this 

 region, growing under favourable circumstances to 4 m. in height. 

 In exposed situations upon the coast the latter species becomes 

 prostrate, and the extraordinary appearance of a mass of writhing, 

 fleshy arms presented by ancient specimens, leafless, contorted, riven 

 and half dead, is as remarkable as any aspect of vegetation in the 

 island. Very similar in appearance to Euphorbia regis-Jubce is 

 Kleinia nereifolia ; it has the habit of a miniature dragon-tree and is 

 in fact an arborescent Senecio. 



Considerable uniformity marks the vegetation of this desert- 

 belt, which is found bordering the whole of the south-eastern coast. 

 It is prolonged up the south-western coast and even extends round 

 the promontory of Teno to Buenavista on the northern coast, where 

 all the plants mentioned, including Ceropegia, were seen in profusion, 

 with the addition of the curious Euphorbia aphylla. From this point 

 onward the steeper and comparatively well-watered slopes of the 

 northern coast allow small scope for the development of the desert 

 flora, but wherever conditions are favourable, as where a lava-flow 

 has made its way down to the sea, the familiar forms reappear. 



The genus Statice, nowhere better represented than in the 

 Canaries, is characteristic of the northern coast. 5. arborescens, 

 the finest species, is no longer found in a wild state. S. macro- 

 phylla, little inferior to it, was met with on the coast of the Anaga 

 promontory. Old plants form a woody stock 45 cm. in height, 

 covered by the persistent bases of previous leaves. 



In the remaining and upper part of the coastal region are com- 

 prised all the more fertile parts of the island, though upon the north 

 side banana plantations descend in places almost to sea-level. 

 This region owes such fertility as it possesses to careful distribu- 

 tion of the water drawn from rock-borings in the higher barrancos, 

 and led for miles in a series of stone channels. But nowhere is culti- 

 vation more than partial, and where it fails, as in the dry, rocky 

 ravines and on the old lava-flows, the native flora asserts itself. 

 The Villa de Orotava and Gui'mar, each standing at an elevation of 

 about 330 m., but the one upon the northern and the other upon the 

 southern slope of the central ridge, are excellent centres for the study 

 of the vegetation of this sub-zone. The dependence of fertility upon 

 water supply is nowhere more evident, the appearance of date-palms, 

 maize, orange-trees or bananas invariably indicating the existence of 

 a tank of atarjea. From the scorched, opuntia-grown slopes one 

 drops into the depths of the Barranco Infierno to find a rivulet which 

 might almost be a Hampshire trout stream so familiar is its vegeta- 

 tion of water-cress, Helosciadum, Potamogeton and water-ranunculus, 

 with Epilobium and Mentha on its banks, but the illusion is dispelled 

 by the tall thickets of Arundo donax and the huge leaves of Colocasia. 



