THE AZORES 



425 



such conditions Epilobium would only require an initial elevation 

 of about 17,500 feet. Senecio vulgaris and Sonchus oleraceus would 

 require about 27,000 feet, and Habenaria about 29,000 feet. I am 

 not assuming that any of these flowering plants were introduced 

 into the Azores by the winds. In fact, there is good reason for 

 holding that in the case of the plants with plumed seeds they were 

 introduced as weeds. But it is quite possible that Epilobium seeds 

 might be carried across a tract of ocean, a few hundred miles broad, 

 if they began the passage high up a mountain's side. 



The up-draught that occurs on the slopes of lofty mountains 

 would soon carry the spores of cryptogams to levels several thousands 

 of feet above the sea. These ascending currents, according to 

 Whymper, Humboldt, and others, transport insects up to levels 

 of from 15,000 to 19,000 feet on the Andes, and, as the writer himself 

 observed, to the summit of Mauna Loa in Hawaii, about 13,600 feet 

 above the sea {Plant Dispersal, p. 585). As discussed in the work 

 just quoted, they form an important factor in the climatic regime 

 of mountain regions, and as such they are treated by Samler Brown 

 in the case of the Peak of Teneriffe in his Guide to the Canary Islands 

 (1905, pp. e24-e29). 



The most pertinent example of oversea transport of seeds by the 

 winds that can be quoted in this connection is that given by Warming 

 in his writings on Greenland and the Faroe Islands, and referred to 

 by Sernander in his work on Scandinavian vegetation. Here large 

 quantities of plant debris, mostly fruits of Calluna vulgaris mixed 

 with blossoms of Erica tetralix, were, during a gale in February 1881, 

 blown across the Cattegat from the Swedish coast to the eastern 

 shores of Jutland, a distance of 110-120 kilometres. But if we wish 

 to believe that the islands of the Azores were originally stocked with 

 Calluna vulgaris in this manner, we are concerned with transport 

 over a tract of ocean thirteen times as broad as the Cattegat. It 

 is not possible to deal further with these matters here, and the reader 

 may be referred for a general discussion of the subject of the wind 

 as a transporting agency to Lloyd Praeger's pages and to Ernst's 

 New Flora of Krakatau. 



Notes on the Plants of the Azores 



These notes may be prefaced with the remark that there is in 

 general a close agreement between the ranges of the altitudes obtained 

 by myself on Pico and those ascertained for the same mountain by 

 Hochstetter, with whose work I was at that time quite unacquainted. 

 Watson (p. 114) writes in a depreciatory tone of the 44 alleged ranges 

 of altitudes " given in Seubert's Flora, and ignores them altogether. 

 They were all derived from Hochstetter, and are in my opinion 

 generally to be relied on. They are often given in the following 

 notes, some of them being taken from the paper by Seubert and 

 Hochstetter in Wiegmann's Archiv. 



Acrostichum squamosum, Sw. — Grows on Pico at altitudes of 2000 

 to 5000 feet. Hochstetter, 2500 to 5000 feet. 



Anagallis tenella, L. — It is singular that a plant so abundant 



