34 
Tansley and Fritsch. 
situations, irregular; but in some cases at any rate it has a 
markedly pyramidal form with an enlarged bushy base, as a result 
of the sprouting of new branches from above the stilt-roots as 
described above (Fig. 11, cf. also Karsten, Bibl. Bot., Heft. 22, 
Tab. I.) 
An interesting feature of the various members of the man¬ 
grove formation is the presence of protective structures enveloping 
the bud; in the Rhizophoraceae these are constituted by the 
stipules, and as Karsten points out (loc. cit., p. 54) large amounts 
of mucilage are excreted from glands borne at their base, and 
this mucilage envelopes the whole bud. Similar glands, according 
to the same author, are found in Sonneratia, Avicennia and 
A egiceras. 
We may perhaps be allowed to call attention to some popular 
misconceptions of mangrove forests. References to “ gloomy, 
fever-haunted mangrove swamps,” with their “ foul, treacherous 
mud,” are often met with. The gloom of a mangrove wood is 
certainly not remarkable, and so far from the light being actually 
dim, Schmidt 1 has recently shewn that it is but little less bright 
than on the open sea, and far brighter than in the shade of an 
inland jungle. The mud is certainly not always stinking, and is 
frequently quite firm enough to bear one’s weight. We have not 
met with the abundance of land-crabs described by some observers, 
but the amphibious fish ( Perioplithahnus ), which spend half their 
time hopping about on land, are numerous and amusing. 
Rhizopliora and Bruguiera, when well grown, are undoubtedly both 
handsome trees, and a fringe of mangroves with their thick dark 
green glossy foliage is certainly an embellishment of the shores of 
tropical estuaries. 
Next in importance to Rhizopliora and Bniguiera, among the 
Ceylon mangroves, comes Sonneratia acida. This species is very 
abundant and widely spread in the mangrove formation of the 
Ceylon coast, sometimes occupying a front situation on the shores 
of the estuaries and lagoons, and very often figuring largely in the 
tree vegetation of the stretches of muddy soil more or less affected 
by the tide behind the fringe of mangroves on the actual water’s 
edge. In the last situation Sonneratia really belongs more to the 
“semi-mangrove” vegetation (see below) than to the true 
mangrove-formation. Sonneratia acida varies in stature from a 
1 Schmidt, loc. cit., p. 12. The sensitive paper of the actinometer 
took on the standard tint after the following exposures; 
open sea, J to ^ sec.; under the shade of a lihizophora 
conjugata, 2 secs.; in an inland jungle, 90 secs. 
