THE CONQUERING TREE 199 



age when the earth was enveloped in clouds and mist ; and 

 that with the gradual decrease in tepid aqueous vapour the 

 viviparous habit, then almost universal, was lost, except in 

 the case of this plant. Other plants, however, exhibit the 

 characteristic. Notably one of the handsomest of the 

 local ferns {Asplenium bulbiferuni) 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, water- 

 logged 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 



