336 A TEXT-BOOK OF BOTANY 
to swamp thickets, is a very natural one, each one often 
passing gradually into the next. 
197. Peat-bogs.—This is a peculiar kind of swamp 
association, characterized by the abundant growth of the 
bog- or peat-moss, and developed in undrained swamps. 
Growing out of the springy moss turf there are numerous 
peculiar plants, such as heaths (Fig. 305) and orchids, and 
the curious carnivorous plants (§ 20). 
198. Swamp forests.—Often trees encroach upon peat- 
bogs, and a swamp forest is the result. The chief types in 
this case are the conifers, and on this bog-moss foundation 
there occur larches, certain hemlocks and pines, junipers, 
etc. The larch or tamarack is a very common swamp 
tree of the northern regions, usually occurring in small 
patches; while the larger swamp forests are composed of 
dense growths of hemlocks, pines, etc. (Fig. 306). 
199. Salt marshes and meadows.—The salt marshes and 
meadows near the seacoast are well known. They lie 
beyond the reach of ordinary flood-tide, but the waters are 
brackish. In these marshes occur certain characteristic 
salt-water grasses and sedges, giving the meadow-like ap- 
pearance; while associated with them there are numerous 
succulents, that is, fleshy plants, characteristic of brackish 
water. 
200. Mangrove swamps.—This is the most vigorous salt- 
water association. Mangrove swamps occur along flat 
tropical seacoasts where the waters are quiet (Fig. 307). 
The mangrove is a tree of curious habit, advancing slowly 
out into the water by means of its prop-roots and peculiar 
seeds. The seeds germinate while still upon the tree, so 
that the embryos hang from the trees and then drop like 
plumb-bobs into the muck beneath, where they stick fast 
and establish themselves. 
