410 PLANTS, SEEDS, AND CURRENTS 



feet lower than on Teneriffe, that is to say, between 2500 and 4500 

 feet above the sea. Here, usually under good soil-conditions, the 

 Juniper is at home on Pico, but there are no Pines. The absence 

 of the Pine from Pico, and from the Azores as a group, is a very 

 pregnant fact in the history of the plant- stocking of the archipelago. 

 A brief comparison of the summit vegetation of the great volcanic 

 mountains of Teneriffe and of Pico, as well as of Madeira, will follow 

 the description of the zones of vegetation on the last-named island. 



In the case of Madeira, sufficient materials for the comparison of 

 its zones of vegetation are supplied by Lowe. The lowest or tropical 

 zone, corresponding to the African zone on Teneriffe, extends accord- 

 ing to this authority only 700 feet up the slopes. He names it the 

 Cactus and Banana zone, and names among its indigenous plants 

 Draccena draco and Euphorbia piscatoria (the Dragon Tree and arbores- 

 cent Euphorbia of the lowest Canarian zone), with species of Semper- 

 vivum, and the sapotaceous tree, Sideroxylon mermulana ; but we 

 may infer that both in its extent and its characters the lowest 

 Madeiran zone is a poor representative of the Canarian zone. From 

 the data given by Lowe we can infer that the woods which originally 

 clothed the slopes of Madeira from five or six hundred feet above the 

 sea to within a few hundred feet of the summit, the altitude of which 

 is about 6100 feet, were in the main the representatives of the Laurel 

 woods of Teneriffe, which there exist at levels of 2000 to 5000 feet. 

 In their lower levels flourished, as in the Azores, the Faya tree (Myrica 

 fay a), and in the upper levels the Azorean Laurels Laurus indica and 

 L. canariensis), all characteristic of the Canarian woods. They were 

 associated with the Tree-Heath (Erica arborea) of Teneriffe, Rhamnus 

 glandulosa of the same island, the Tree-Euphorbia (E. mellifera), 

 and Picconia excelsa of the woods of Pico and Teneriffe, besides 

 shrubby species of Hypericum and Vaccinium, representing pre- 

 dominant plants of the Azorean and Canarian woods. But a feature 

 of the Madeiran as well as of the Canarian woods, a feature not 

 possessed by those of the Azores, is the presence of shrubs and trees 

 of the American genera, Clethra, Cedronella, and Bystropogon, etc., 

 to the significance of which allusion will subsequently be made. 



There was originally a Juniper zone in the higher levels of the 

 Madeira woods, such as there was once on Teneriffe, and such as 

 exists now on Pico. Though now nearly exterminated on account 

 of the value set on its timber, Juniperus oxycedrus, as Mr. Johnson 

 tells us (Encycl. Brit. 9th edit. XV., 180), was formerly abundant, 

 and grew to a height of forty or fifty feet. Its lower limit was pro- 

 bably intermediate between that of the Juniper zone on Pico (2000 

 feet), and on Teneriffe (4000 feet), so that probably it would have 

 flourished at levels above 3000 feet. Walker, in his book on the 

 Azores, speaks of this Juniper as growing to a stately size in the 

 mountain fastnesses of Madeira. Indigenous Pines are absent from 

 Madeira as well as from the Azores, and the same difficult question 

 is here raised. Since Pinus pinaster has been extensively planted 

 on the Madeiran slopes, the absence of the genus cannot be due to 

 unsuitable conditions. 



It is remarkable that whilst the woods of Pico, Madeira, and 



