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It is remarkable that the borders of certain sandbanks are, so to say, studded with rare 

 plants, coining from higher latitudes or regions Such isolated banks are met with often 

 at great distances, and are at the same time more than others subject to be carried away by 

 floods during the rainy season. I suppose, that it is hardly the prevalent current, which 

 carries the seeds of such plants on to these favoured banks, while all others, although quite 

 similarly circumstanced, are destitute of tliem. 



^ACcfiATwrn. ST)ontMTiU'irv urvdv ^cmte,fei. coar-ae herbs'. 



Section of a sanctbani. 



The above sketch of a section of such a sand bank will give an idea of the configuration 

 of the terrain, shewing at the same time, that it is the gradual, and not the abrupt, slope, 

 along which such rare plants, as are termed more correctly fugitives, may be found. The 

 sand is there usually mixed with a considerable proportion of vegetable mould. 



b. Vegetation of streams, etc., with a rocJaj or stony bed. The vegetation of the rocky or 

 stony beds is restricted more to the upper parts of the streams, etc. ; but those choungs that 

 do not enter the alluvium, possess solely rock bed vegetation. Accordingly, as the course of 

 such choungs is through leaf-shedding, or through evergreen forests, the change in the vege- 

 tation is marked by the absence or presence of xerophilous or hygrophilous plants. 



On such rocky or stony beds do by preference grow : Rungia pectiiiata, Cijclocodon trun- 

 catiim and a fine large white-flowered Lobelia {L. Wallichiana, especially on sand-stone rocks), 

 Pentasacmc caudatum, Canscora diffusa, Rliabdia riminea, Lindenbergia urticaefolia and Philip- 

 pinensis, Torenia parvijfora and cordifolia, Ajiiga decumbens, Celosiaargentea, Gyathula prostrata, 

 Pouzolzia Indica, Crypfocoryne spiralis, Lasia aculeata, Crotalaria ferruginea, Ophiorrhisa, 

 Goodyera procera ? , Selaginella tenera and imbricata, Cyathocline lyrata; Pogonatherum, 

 Eqimetum debile, 2 or 3 species of Nephrodium, several species of Elatosteinma, Plectrantluis, 

 Polypodiiun pteropiis, Oymnopteris, Adiantum lanulatuni, Trichomanes Jacanicum, Hymeno- 

 phyllitm, some species of Eragrostis, Cyperisp., Polygonum, Asjileiiium esculentum, Thyssanolaena 

 acarifera, Dysojihylla, etc. 



Between the rocks, growing on the pebbly ground, many a shrub settles itself in spite 

 of the torrents during the rains. Such are Salix tetrasperma, Sarcochlainys pulcherrima, 

 Cassia palmata, Ficus ischnopoda and another allied species, Homonoya riparia, Dchregeasia 

 telutina, Bohmcria Malabarica, Eugenia contracta ? and a few others. 



When the course of such choungs leads through evergreen forests, the rocks and boul- 

 ders are usually covered by cryptogams, such as Marchantia, Metzgcria, Fissidens, Hypiuim 

 and other species, between wliich grow several species of Elatosteinma, Selaginella semicordata 

 and tenella, Trichomanes^ Hymenophylla, etc. 



Certain trees also shew a particular predilection for such hill streams, like Eugenia macro- 

 cnrpa, Macaranga Indien, Cassia Timorensis (mayzelee) Bischoffia Javanica, Erythrina litliosperma, 

 Euphorbia antiquorum ? , and neriifolia, a white flowered Ixora, Ficus glomerata and macrophylla, 

 Dillenia Indica, Gitnizanthus, Cassia palmata. Calamus arborescens, Trewia nudiflora, and others. 



A curious ochre-yellow Alga (Leptothrix ochracea,) is met with frequently in many 

 localities of hill choungs, protruding from amongst soft sandstone or moist walls of 

 the same rocks forming sometimes a soft jelly-like mass, half a foot thick, which on closer 

 microscopical examination is found to be composed of very thin fragile filaments, giving a 

 peculiar amianthlike structure to the slabby mass. 



Other ochre or rust-coloured matters are frequently seen in and along the numerous 

 trickling wells of the alluvium, floating like an oily sheet on the surface of stagnant little 

 pools, encrusting the plants growing in the neighbourhood, or depositing themselves on the 

 ground. These substances, however, are possibly nothing but iron oxydes, sometimes 

 transforming into what is called Rasenerz. Only Diatoms are fouud in such places, but rarely 

 other Algce. 



B.B. Vegetation of the swamps and waters. 



I will now refer to the vegetation that grows in a medium of sweet or salt water. 

 Most of the water plants, however, root in the ground, and derive therefore their nour- 

 ishment from the soil, in which they grow. Comparatively few of these are suspended, 

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