CH.XIV LITTORAL AND INLAND PLANTS' RELATIONSHIP 131 



There are, it is true, a few current-borne plants that one meets 

 everywhere. For instance, Convolvulus soldanella is to be 

 gathered on English beaches and on those of New Zealand and 

 of the coast of Chile. But these littoral plants with buoyant 

 fruits hardly give a feature to the strand-flora. A multitude 

 of intruders, either characteristic of the inland flora of the region 

 or confined only to the seaboard of that part of the world, 

 also make their home on the beach and frequently endow a 

 beach-flora with its leading features. The possible associations of 

 plants on a beach in a temperate region are thus very great ; and 

 I have already discussed this in part in Chapter IV. as concerning 

 the British shore-flora. One has only to look at a work like that 

 of Dr. Willkomm on the vegetation of the strand and steppe- 

 regions of the Iberian peninsula to realise how the few littoral 

 plants familiar to the English eye cut but a sorry figure amongst 

 the numbers of strange intruders from the arid regions inland. 

 So again, as I found on the Chilian beaches, Convolvulus 

 soldanella finds odd associates amongst the species of Nolana 

 and Franseria that are peculiar to the coasts of that part of the 

 globe (see Chapter XXXII.) ; and different grotesque American 

 forms of the Cactaceae with a Mesembryanthemum and a host of 

 strange-looking plants descend from the arid slopes of the hills 

 behind to keep company with the far-travelled English beach- 

 plant (see Note 49). Or again, a glance at the pages of Professor 

 Schimper's great work on Plant- Geography will bring the same fact 

 home in a still more varied fashion. 



Yet on tropical coasts the intruding inland element is also 

 distinguishable, though it may influence only to a small degree the 

 general character of the strand-flora. Dividing it, as we have 

 described in Chapter V., into the plants of the sandy beach and of 

 the mangrove-swamp, we find in the mangroves the most stable 

 element and in the beach-plants those most liable to change. 

 Professor Schimper observes that whilst the physiognomy of the 

 beach-flora varies to some extent with the alterations in the inland 

 flora, the mangrove-formation makes but a slow response to such 

 changes. As he points out in his work on the Indo-Malayan 

 Strand-Flora (p. 199), seeds and seed vessels are being continually 

 brought down to the sea-coast through the agencies of rivers, 

 winds, and birds ; and in this manner, in the course of ages, the 

 beach-flora is recruited from the inland plants. But for the 

 mangroves such additions to their numbers are rarely possible. 

 Whilst the same genera are often shared by both the beach 



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