34 



A NATURALIST IN THE PACIFIC chap. 



sometimes at considerable elevations in mountainous districts, as in 

 Central Europe. It is on this occurrence of certain shore-plants in 

 alpine regions that Prof. Schimper lays much stress in his 

 memoir on the Indo-Malayan strand-flora (p. 28), and in his later 

 work on Plant Geography (Engl, edit., p. 716), when pointing out 

 that here temperature does not play a determining part, and that 

 in both stations, whether on the sandy beach or on the mountain- 

 top, the same xerophilous organisation is needed to obviate the 

 risk of impeded water-supply. He quotes in this connection 

 the observation of Battandier that many alpine species from 

 the Atlas Mountains occur on the Algerian beaches, but not in 

 intervening regions. Mr. Druce, in his discussion of the British 

 species of Sea-Thrifts and Sea-Lavenders (Armeria,Statice), brought 

 the subject of the occurrence of maritime plants on mountain sum- 

 mits again to the front ; but he did not advance any general 

 explanation, and seems to regard it as the result, as it doubtless 

 is, of the recurrence of suitable stations (Jour. Linn. Soc. Bot., 

 Dec. 1900). 



Very few of these plants have any capacity for dispersal by 

 currents, a subject dealt with in Note 16. Several of them have 

 dehiscent, small-seeded fruits which, as pointed out in the previous 

 chapter, hardly ever come into the buoyant category. I have 

 experimented on the greater number of them, and in only one 

 species, Matricaria inodora (var. maritima), do the results indicate 

 a capacity for dispersal over wide tracts of sea. 



If we look again at a list of British shore-plants, we find 

 another group of plants frequenting salt marshes and muddy 

 shores, and found also often far inland, as in the saline plains 

 of Central Asia. Here we have such plants as Aster tripolium, 

 Glaux maritima, Plantago maritima, Salicornia herbacea, Salsola 

 kali, Samolus valerandi, Scirpus maritimus, Suaeda fruticosa, 

 S. maritima, Triglochin maritimum, T. palustre, &c. It becomes in 

 this connection a subject of peculiar interest to the student of plant- 

 distribution when he reads in Mr. Hemsley's paper on the flora of 

 Tibet {J our. Linn. Soc. Bot., vol. 35) that amongst the British shore- 

 plants above-named the two species of Triglochin and the same 

 species of Glaux and Salsola occur in the salt marshes of the Tibetan 

 uplands at elevations of 15,000 to 16,000 feet, Scirpus maritimus 

 also being found in the swamps of the lower levels. We have the 

 same thing, affecting much the same plants, illustrated in America. 

 Thus we learn from Asa Gray that Salicornia herbacea, Scirpus 

 maritimus, Triglochin maritimum, &c, which are common in salt 



