4 Salter, Flora of Teneriffe. 



Their soil, often a fine red loam, retains more moisture than do the 

 porous deposits (ash, lava, cinders, sand) characteristic of the re- 

 mainder of the island. Anaga receives the first onfall of the rain- 

 clouds brought by the north-east trades. Hence Ranunculus 

 cortuscefolius , which at Guimar is a plant of the moist barrancos 

 (760 m.), grows near Taganana almost to sea-level and Genista 

 canariensis descends noticeably lower than it does elsewhere. Both 

 regions possess a number of plants which do not occur elsewhere in 

 the island or are highly characteristic. 



The Zones of Vegetation 



Humboldt recognised four of these regions, proceeding from 

 sea-level : 



(1) (Zone of the Vine.) Characterised by tree-like species of 

 Euphorbia, Draccena and Sempervivum, and by shrubby species of 

 Sonchus. 



(2) (Zone of the Monte Verde.) Laurels, holly, arbutus, ferns. 



(3) (Zone of the Pinar.) Pinus canariensis, with Myrica fay a 

 and Erica arbor ea. 



(4) (Above the Tree Limit.) Retama {Spartocytisus) and a few 

 herbaceous plants and grasses. 



Dr. Christ prefers a subdivision into three great belts : 



(1) The Coast Region. From the seashore up to about 610 m. 

 (2000 ft.). Characterised by the occurrence of Opuntia. 



(2) The Cloud Region. Commonly occupied by the cloud-belt. 



(3) The Alpine Region. Above the cloud-belt. 



It will be seen that upon this view the cloud region corresponds 

 to Nos. 2 and 3 of Humboldt's series, while both agree in recognising 

 a coastal and an alpine region. 



It is evident that the zones can only be characterised in general 

 terms and that they are separated by no hard-and-fast lines. Thus 

 if we accept Christ's coast region it must be with the proviso that the 

 plants growing at sea-level are an entirely different series from those 

 met with at the upper limit of this zone, where, immediately under 

 the cloud-belt, cooler conditions prevail. No single species can be 

 taken as giving an exact indication, since the range of nearly all 

 extends higher upon the southern side of the central ridge than upon 

 its northern slope. Thus Opuntia, which above Guimar ceases at 

 730 m., was noticed at Vilaflor extending in a warm barranco up to 

 the skirts of the pine forest, while Euphorbia regis- Jubae attained 

 to very nearly the same level. 



Taking the limit of the coastal belt upon the southern side of 

 the island at 730 m. (2400 ft.), its composite nature may be shown by 

 a subdivision as follows : — 



(1) Foreshore. 



(2) Desert (stony, rocky or black sand). 



(3) Orchards, plantations, vineyards (banana, tomato, orange, 

 vine). 



(4) Cultivated lands (wheat, potatoes, lupins, broad beans). 



