RHIZOPHORA MANGLE 



105 



conveniently described under three heads : (a) the aquatic and semi- 

 aquatic plants of the river and the riverside; (b) the plants of the 

 Great Morass, a region of swamp traversed by the Black River and 

 its tributaries ; (c) the plants of the mangrove formation. 



(a) The Plants of the River and the Riverside. — Lining the banks 

 above the mangroves is a tall reed-growth of Cyperacece (Cyperus 

 elatus, etc.) and Typha angustifolia, with which are associated 

 Sagittaria lancifolia, which attains a height of four or five feet, 

 Chrysodium vulgare (the Swamp Fern), a species of Jussi&a, Pavonia 

 corymbosa (a malvaceous shrub), Polygonum glabrum, etc., all of 

 which grow more or less in the water or in the swampy borders. In 

 the shallows grow the Water Hyacinth (Pontederia) and Nymphcea 

 ampla, the last covering the large expanses of water into which the 

 rivers occasionally broaden out. Amongst the more or less sub- 

 merged aquatic plants are Utricularia (near U. obtusa), Potamogeton 

 plantagineus, Ceratophyllum demersum, Isnardia palustris, Hydrocotyle 

 umbellata, etc. Pistias grow scantily in the recesses of the banks of 

 the main channels, but are especially abundant in the vicinity of the 

 springs that well up in different localities of the Great Morass, and 

 nestling amongst them little floating masses of Azolla may be at 

 times observed. 



(b) The Vegetation of the Great Morass in the Black River District. — 

 This broad, savannah-like region, elevated but a few feet above the 

 sea, extends some six or seven miles inland to the foot of the moun- 

 tains. Looking down upon it from the slopes behind, one would 

 imagine that one was gazing at some arid plain where clumps of tall 

 palms serve to vary the monotony of a landscape in which Nature 

 has been niggard in her ways. This notion would receive fresh 

 colour when we observed the rivers winding through the plain and 

 the dark green belts of trees that in places marked their courses. 

 Yet we are not looking at a waste but at a swamp, where the ground 

 is soaked with water as a sponge, where copious springs well up, and 

 where the alligator finds a home. 



The tall palms are the Thatch Palms (Sabal umbraculifera), and 

 they grow in the midst of a swamp- jungle largely composed of a 

 reed-growth of Typha, Cyperaceae, and other similar plants. We 

 should often find no footing in the marshy ground ; and if we wished 

 to examine the district, we must pole along in a canoe through 

 narrow channels more or less blocked by vegetation. In one place 

 we should be traversing an area of several acres occupied only by 

 Scirpus plantagineus, growing to a height of three feet, and sugges- 

 tive in its appearance of an Equisetum. In another place we should 

 find the surface carpeted with Herpestis monniera. A third locality 

 would be appropriated by the Swamp Fern (Chrysodium vulgare). 

 But more often the eye would rest on the tall reed-growth of grasses 

 (Arundo, etc.) and sedges (Cyperus, etc.) and bulrushes (Typha) that 

 monopolises most of the surface. Conspicuous amongst the swamp 

 vegetation are the Pavonia trees, or rather shrubs (P. corymbosa) ; 

 whilst, strangely enough, Conocarpus erectus, a plant typically 

 halophilous in its station, is one of the most frequent among the smaller 

 trees in this fresh- water morass in places where the ground is firmer. 



