CHAPTER XIX 



the azores (continued) 



The Relation between the Differentiating Influences and the Dispersing 

 Agencies. — Before referring to the modes of dispersal of the plants 

 of different stations, I will briefly indicate how we may interpret 

 the relation between the differentiating influences and the dispersing 

 agencies. Though the specific divergence of most of the plants 

 of the woods of the Azorean islands indicates a breaking of the link 

 established by frugivorous birds with their European home, there 

 is an important minority, as before remarked, made up of plants 

 specifically identical with those of Europe, which testify that a 

 connection has sometimes been maintained down to recent times „ 

 The majority include plants of the genera Hedera, Ilex, Laurus T 

 Myrica, Rhamnus, Smilax, Vaccinium, etc., and the minority com- 

 prise species of Daphne, Juniperus, Viburnum, etc. But even with 

 the minority there are signs of the rupture of the connection with 

 the continent. Thus Juniperus oxycedrus has developed an Azorean 

 variety (var. brevifolia) which has puzzled the botanist, and Viburnum 

 tinus has developed an Azorean form (var. subcordata) which according 

 to Trelease seems to be nearer to a Canarian species than to the 

 parent species of the neighbouring continent. Looking at these 

 facts we may regard the connection between the plants of the woods; 

 of the Azores and those of Europe as either broken or breaking. 

 But the connection has been kept up with Madeira and the Canaries, 

 and it would seem that in recent times the activities of frugivorous 

 birds as dispersing agents have been mainly restricted to the Macaro- 

 nesian region. It is very different, however, with the plants of the 

 mountain moors and with the aquatic and subaquatic plants, where 

 the community with European species leads one to infer that the 

 connection by birds has been usually continued down to recent times. 



The Modes of Dispersal of the Plants of the Azores. — Generally 

 speaking, the prevailing shrubs, trees, and climbers of the woods are 

 known to be dispersed, or are regarded as likely to be dispersed, by 

 frugivorous birds, such as those of the genera Daphne, Hedera, Ilex, 

 Juniperus, Laurus, Myrica, Rhamnus, Smilax, Taxus, etc.; whilst 

 the plants of the dry and wet upland moors of the genera Anagallis, 

 Calluna, Carex, Hydrocotyle, Menziesia, Polygala, Potentilla, Thymus, 

 etc., as well as those of the waters and of the borders of ponds of 

 the genera Callitriche, Littorella, Peplis, Potamogeton, Scirpus, etc. 3 . 

 possess small and often minute seeds or seed-like fruits, for the 

 dispersal of which we must look to birds of other habits. The seeds 

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