386 PLANTS, SEEDS, AND CURRENTS 



side and the upper woods on the south-eastern side. They are 

 essentially formed of evergreen shrubs and trees; but on account 

 of the persistent agency of the woodcutter through centuries the 

 trees, except when specially preserved, rarely exceed twenty feet 

 in height, and are usually not more than fifteen or sixteen feet. 

 Dwarfing begins, as a rule, at about 4000 feet, as the effect of deficient 

 -soil and of exposure to strong winds. Above 5000 feet are the 

 sparsely- vegetated, precipitous lava slopes of the cone proper; 

 tbut in spite of the conditions five or six kinds of plants, usually as 

 stunted and creeping growths, reach the summit (p. 367). 



6. The writer then comes to his special study, the zones of vegeta- 

 tion on the great mountain of Pico. This subject is not dealt with in 

 the later works on the flora, which are almost exclusively devoted 

 to the systematic treatment of the plants, and were the only sources 

 of information accessible to him at the time of his visits. The 

 result was that after he had completed his study he found that in 

 the main he had long before been anticipated by the earlier German 

 and French investigators, particularly by the Hochstetters (p. 368). 

 The zones of vegetation adopted by the writer for this mountain do 

 not differ very materially from those of his predecessors. They are 

 as follows : — 



I. The Lower Woods, or the Faya zone, Myrica faya being one 

 of the most characteristic of the trees. The zone extends usually 

 from the coast up to 2000 feet. Besides the Faya, the other trees 

 peculiar to the zone are Bhamnus latifolius, Persea (Laurus) indica, 

 and Picconia excelsa. Among the trees that are abundant in both 

 the Upper Woods and the Lower Woods are Ilex perado, Erica azorica, 

 and Laurus canariensis. Of the shrubs the Laurestinus (Viburnum 

 tinus) is restricted to the zone ; whilst Vaccinium cylindraceum and 

 Myrsine africana, abundant here, are equally common in the Upper 

 Woods. 



II. The Upper Woods, or the Juniper zone. Juniperus oxycedrus 

 (var. brevifolia), Daphne laureola, and Euphorbia stygiana are the 

 most distinctive of the trees and shrubs ; whilst Erica azorica, Ilex 

 perado, Laurus canariensis, Myrsine africana, and Vaccinium 

 cylindraceum are as characteristic of this as they are of the zone 

 below. Taxus baccata, now almost extinct, thrived originally in 

 the lower levels of the Upper Woods and in the higher levels of the 

 Lower Woods. The Loranth, Arceuthobium oxycedri, is a frequent 

 parasite on the Juniper trees. This zone extends usually from 2000 

 .to 4500 feet, but is continued as a scrub up to 5500 feet. 



III. The highest zone of the cone proper, 5500 to 7600 feet. All 

 ^£'he plants growing on these scantily vegetated, steep, lava slopes 

 tiave climbed up from the lower levels, principally from the moors, 

 as described below. They include Calluna vulgaris, Menziesia 

 polifolia, Thymus serpyllum (var. angustifolius), Polygala vulgaris, 

 and Agrostis castellana, all of which reach the summit. 



IV. The zone of the Upland Moors, 2000 to 4000 feet, which has 

 been formed at the expense of the Upper Woods around much of 

 the mountains. Here we find many of the features of a Devonshire 

 moor, as on Dartmoor. The most striking general features are the 



