.iiAr. VI] EDAPHIC INFLUENCES IN THE TROPICS 385 



those of the surrouiicliiig forests, that one must necessarily ask liow all these trees 

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

 -iniilar 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 

 .1 communication by Captain Seaton to Kurz, swamp-forest is complete^ bare of 

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

 111 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 

 -cason 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 verj- peculiar substratum, the tall trees consist of 

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

 pliyllum 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, 

 I'arringtonia acutangula, Dalbergia flexuosa. Among shrubs are in particular 

 I .lycosmis pentapliylla. Capparis disticha, Hymenocardia Wallichii. Grewia sinuata, 

 !'?ilobium sp., Cratacva hygrophila, Combretum trifoliatum. Gardenia sp. The 

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

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

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

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

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

 cladus Griffithii. Combretum tetragonocarpum, Roydsia obtusifolia, Dcrris scandens, 

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

 Wallichii, also Cyperus sp., Fimbristj'lis sp., species of Polygonum, and Maranta. 

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

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



I he water of the pools and swamps is usually very muddj' and poor in plants ; 

 lear clean water never entertains a verj' 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 

 lie covered with water during the rainj- season, but dr}' up more or less completel3' 



II the drj- season and are overgrown with reed-like grass. Kurz has observed 

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

 ■during the drj' season, and covered with soft juicy species of grass like Hymenachne 

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

 lexandra. with a few herbs, such as species of Jussieua and Xj'ris, and these plants 

 n the rainy season form floating meadows. Swamps that even in the drj' season 

 emain very wet, bear either a flora quite similar to that of the periodical!}^ drj- ones or 

 ii'e covered with the reeds Phragmites Roxburghii and other species of Phragniites. 



' Junghuhn, op. cit., p. 20S. 



1 SCHIMPER Q Q 



