BULBIFERUM) which, with motherly solicitude, detains its offspring until they are not only fully developed but are strong and lusty.  As the fronds die they incline earthwards, each weary with the burden of a new and virile generation—­some of which float down stream to foreign parts, some create a colony round the parent.  This fern demands conditions similar to the mangrove—­water, heat and humidity—­and might be quoted in support of the theory which gives unique interest to a mangrove swamp.

Whole battalions of living mangrove radicles fall into the rivers during February and March.  Out at sea miles from the land you may cross the sinuous ranks of the marine invaders—­a disorderly, planless venture at the mercy of the wind and waves.  Myriads perish, hopeless, waterlogged derelicts, never finding foothold nor resting-place.  But thousands of these scouts of vegetation live to fulfil the glorious purpose of winning new lands, of increasing the area of continents.  This arrogant plant not only says to the ocean, “Hitherto shalt thou come, but no further; and here shall thy proud waves be stayed” but unostentatiously wrests from it unwilling territory.

Plants like animals require “food convenient for them,” certain constituents of the soil, certain characteristics of environment, that they may flourish and fulfil their purpose.  This delights in conditions that few tolerate—­saline mud, ooze and frequent flooding by the salt sea.  Drifting into shallow water the sharp end of the spindly radicle bores into the mud.  At once slender but tough roots emerge in radiating grapples, leaves unfold at the other extremity, and the plan of conquest has begun.  During the early period of its life there is nothing singular in the growth of the plant In a few months, however, it sends out arching adventitious roots, which on reaching the mud grasp it with strong finger-like rootlets.  These arching roots, too, send out from their arches other roots that arch, and the arches of these similarly repeat themselves, and so on, until the tree is underpinned and supported and stayed by an elaborate and complicated system, which while offering no resistance to the sweep of the seas, upholds the tree as no solid trunk or stem could.  Then from the plan of arches spring offshoots, in time to become trees as great as the parent.  Aerial roots start a downward career from the overhanging branches, anchoring themselves in the mud.  Some young seedling drops and the pointed end sticks deep in the mud, and grows forthwith, to possess arching and aerial roots of its own, and to make confusion worse confounded.  The identity of the original founder of the grove is lost in the bewildering labyrinth of its own arches, offshoots, and aerial roots, and of independent trees to which it has given the mystery of life.  One floating radicle with its pent-up energy, having after weeks of drifting and swaying this way and that to the slightest current and ripple, grapples Mother Earth and makes a law to the ocean.  Among the interlacing roots seaweed, sodden driftwood and leaves lodge, sand collects, and as the level of the floor of the ocean is raised the sea retires, contributing by the flotsam and jetsam of each spring-tide to its own inevitable conquest.