Chap. VI] EDAPHIC INFLUENCES IN THE TROPICS 385 



those of the surrounding forests, that one must necessarily ask how all these trees 

 come here. The greater part of them do not occur anywhere but in swamps or 

 similar watery places, and, absent from large tracts of country, they reappear in 

 widely separated spots that are adapted for their growth. They might be called 

 the mangrove-forest of the fresh waters, the ground on which they grow being 

 almost as exposed and swampy as that of the mangrove-swamps.' According to 

 a communication by Captain Seaton to Kurz, swamp-forest is completely bare of 

 leaves in the height of the rainy season. Swamp-forest appears in Burma chiefly 

 in the deep alluvial soil of the Irawadi valley, but also along the Sittaung and at the 

 base of the Yoma Hills. It occurs in a typical form in localities which in the rainy 

 season are covered by water up to 4 or 5 feet (sometimes even 7 feet). It consists, 

 like rain-forest, of several tiers : tall trees 60-70 feet high, small trees, shrubs, 

 and plants clothing the ground. 



As in most formations with a very peculiar substratum, the tall trees consist of 

 only a few species : Anogeissus acuminatus, Mangifera longipes, and Xantho- 

 phyllum glaucum are by far the most prominent. The smaller trees are more 

 diverse ; the most commonly seen are Memecylon Helferi, Elaeocarpus photiniae- 

 folia (?), Pavetta parviflora and P. nigricans, Gonocaryum Lobbianum, Symplocos 

 leucantha, Glochidion sp., Hemicylia sumatrana, Flacourtia sp., Cassia Fistula, 

 Randia sp., two species of Eugenia, two species of Aporosa, Garcinia succifolia, 

 Barringtonia acutangula, Dalbergia flexuosa. Among shrubs are in particular 

 Glycosmis pentaphylla, Capparis disticha, Hymenocardia Wallichii, Grewia sinuata, 

 Psilobium sp., Crataeva hygrophila, Combretum trifoliatum, Gardenia sp. The 

 lianes are numerous and many of them very peculiar, as they possess a short stem 

 that reaches only to the surface of the water during the rainy season, and from 

 which there rise disproportionately long and curved shoots, which form an impene- 

 trable thicket; amongst them are Jasminum sp., Gmelina asiatica, Pachygone 

 odorifera, Sphenodesme erysiboides, Tetracera sp., Acacia pennata (?), Ancistro- 

 cladus Griffithii, Combretum tetragonocarpum, Roydsia obtusifolia, Derris scandens, 

 D. elegans, D. uliginosa. The terrestrial herbs are scanty and consist chiefly of Carex 

 Wallichii, also Cyperus sp., Fimbristylis sp., species of Polygonum, and Maranta. 

 Orchids abound as epiphytes, especially near small lakes. Accompanying them 

 are large ferns such as Asplenium Nidus, and numerous mosses and liverworts. 

 The water of the pools and swamps is usually very muddy and poor in plants : 

 clear clean water never entertains a very rich flora of common fresh-water plants. 



Besides the forest-clad swamps, there are others that resemble oases of grassland 

 in the midst of the forest. Thus Junghuhn ] describes swamps in East Java that 

 are covered with water during the rainy season, but dry up more or less completely 

 in the dry season and are overgrown with reed-like grass. Kurz has observed 

 perfectly similar formations in Burma, where they are sometimes free from water 

 during the dry season, and covered with soft juicy species of grass like Hymenachne 

 Myurus and H. interrupta, Panicum Crus-galli and P. antidotale, Isachne sp., Leersia 

 hexandra, with a few herbs, such as species of Jussieua and Xyris, and these plants 

 in the rainy season form floating meadows. Swamps that even in the dry season 

 remain very wet, bear either a flora quite similar to that of the periodically dry ones or 

 are covered with the reeds Phragmites Roxburghii and other species of Phragmites. 



1 Junghuhn, op. cit., p. 208. 



SCHIMPER Q Q 



