CHAP. LVii PSAMMOPHILOUS HALOPHYTES 229 



tissimus, which resemble species of Rhizophora in growth, as their prop- 

 roots serve to fix them in a loose soil.^ 



Coccoloba-association. Here also must be placed the West Indian 

 Coccoloba-association, where C. uvifera dominates in the form of a small 

 tree or shrub with large, very rigid leaves, which are directed sharply 

 upwards - ; it produces bushland on the shore, and may possess creeping 

 iDranches that strike root. Intermingled with it are many other species 

 of shrubs and herbs, including some belonging to species or genera that 

 occur in Asia. 



Restinga. Allied to these is the Brazilian ' restinga '-forest, which 

 in many respects recalls the campos serrados, described in Section XIII 

 LS present in the interior of Brazil. These littoral forests form a transi- 

 tion to ordinary xerophytic forests ; for the crooked stems and branches 

 often encountered in some of the latter forests also occur here ; the 

 leaves in some species are coriaceous, stiff, thick, and possessed of hairs, 

 without being fleshy, but in others are fleshy and glabrous. Cactaceae 

 <md BromeUaceae play a prominent part. Restinga-forest in Brazil appa- 

 rently is not strictly confined to the sea-shore, as, according to Schenck,^ 

 it can penetrate far inland where no saline soil occurs. 



The seeds and fruits of plants belonging to these tropical, littoral 

 forests are frequently adopted for transport by water, as was demon- 

 strated by Hemsley and Schimper.^ 



Aphyllous hahphytic forest. In addition to true forest on saline sand 

 there is in Central Asia a special association produced by the saxaul- 

 tree, Haloxylon Ammodendron, which belongs to the Chenopodiaceae. 

 This tree attains a height of five or six metres, and its trunk a thickness 

 of twenty centimetres ; its grey, curved and twisted trunk, with its 

 numerous, scaly, thin, short-segmented branches, resembles a 'gi-een 

 besom '.^ It produces a forest which recalls Casuarina-forest in Australia, 

 as the tree is devoid of needles or foliage, yet it is green and bears 

 flowers. (The wood is hard, very brittle, and without annual rings.) 

 Added to this tree are a few other species, including Calhgonum persicum 

 and Pteropyrum Aucherii ; and here one also finds the root-parasite 

 Cistanche tubulosa with dirty-violet flowers. 



The amount of salt in the tnmk is considerable, that in the cortex 

 being 6-25 per cent. ; even the epidermal walls are permeated by fine 

 crystals and similar deposits. Excreted masses of hygroscopic salts 

 serve to absorb dew by night. The cork is so constructed that certain 

 mucilaginous swelling layers take up water ; when the supply of water 

 ceases the production of mucilage is arrested and protective cork once 

 more appears. In addition, numerous idioblasts containing tannin occur. 

 Assimilatory activity is maintained by the production of chlorophyll in 

 the secondary cortex.^ 



Tamarisk-hushland. Halophilous tamarisk-bushland arises locally in 

 Asia and in Mediterranean countries ; it may attain a quite considerable 



' Regarding the flora of Singalcsc shores, see Tansley and Fritsch, 1905. 

 ^ Figured by Warming in Borgesen and Paulsen, 1900. 



' See Schenck, 1903 a. * Hemsley, 1885 ; Schimper, 1891 ; Guppy, 1906. 



'' Basiner, 1848. 



In regard to the remarkable adaptive features of the saxaul-tree, reference 

 should be made to B, Jonssen, 1902. 



