370 PLANTS, SEEDS, AND CURRENTS 



the plants of the Faya and Juniper zones intermingle ; but as a rule 

 the Juniper begins where the Faya ends. The three most distinctive 

 trees and shrubs of this zone are in their order of frequency, Juniperus 

 oxycedrus (var. brevifolia), Daphne laureola, and Euphorbia stygiana, 

 the Tree-Euphorbia. But Erica azorica (Tree-Heath), Laurus 

 canariensis, Myrsine africana, Ilex perado, and Vaccinium cylin- 

 draceum, all of the lower woods, are here also abundant ; and charac- 

 teristic among the ferns are Dicksonia culcita and Acrostichum 

 squamosum, with Woodwardia radicans on the sides of the gulleys. 

 A common parasite on the Juniper trees is Arceuthobium oxycedri. 

 In the original forests Taxus baccata thrived in the lower levels of 

 this zone. 



III. The Calluna, Menziesia, and Thymus zone, 5500 feet to the 

 summit (7600 feet), the cone proper. Mats of Calluna vulgaris and 

 of Thymus serpyllum (var. angustifolius) and tufts of Menziesia 

 polifolia predominate on these scantily vegetated steep slopes of 

 lava and cinders. Polygala vulgaris also occurs with one or two 

 grasses, such as Agrostis castellana. 



There is a close agreement between my predecessors and myself 

 as to the five plants that exist in the higher levels of the peak. All 

 of us, Hochstetter in 1838, Watson in 1842, Morelet in 1857, and the 

 writer in 1913 and 1914, record the Ling {Calluna vulgaris) and the 

 Thyme, and three of us the Polygala, the Menziesia, and the Agrostis. 

 The strangest reference is to the Polygala, which owes its occurrence 

 at this elevation to the protection it finds in the beds of Ling. A 

 solitary specimen was found by Watson in this locality (Lond. Journ. 

 Bot., II., 394) ; but the plant is frequent enough to be regarded as 

 one of the characteristic terminal species, and as such it was rightly 

 viewed by Seubert and Hochstetter. 



Though the number of terminal species does not seem to have 

 increased in the interval between 1838 and 1914, it is likely that the 

 Ling, the Thyme, and the Menziesia have considerably extended 

 the area occupied by them on the level shoulder on the south side 

 of the mountain between 6500 and 7000 feet above the sea. With 

 the exception of Polygala vulgaris, all the plants of the highest levels 

 on Pico are widely distributed over the group. They are not neces- 

 sarily summit plants, but have found a home in the highest levels 

 because they alone of the plants of the lower levels, more especially 

 of the moors, have been able to establish themselves there. Polygala 

 vulgaris has been only found on the island of Pico, where it was collected 

 on and near the summit of the great mountain by Hochstetter in 1838, 

 by Watson in 1842, and by myself in 1914 ; but as below observed 

 I found it also on the moors below, as well as in those of the lake 

 district to the eastward. Agrostis castellana, as we learn from 

 Trelease, is a polymorphous Spanish species that is widely distributed 

 in the Azores, being the most abundant of the native grasses. It is 

 important to note that all the plants that have reached the top of 

 the great cone of Pico have climbed the slopes from the moors below. 

 There is no peculiar summit flora. 



IV. The Upland Moors, 2000 to 4000 feet. This zone has been 

 formed at the expense of the Juniper zone around much of the moun- 



