General 



working green material per square foot of sunlight is 

 almost incalculable. 



It enjoys, of course, maximum sunshine and ample 

 moisture. When either of these factors is at all de- 

 ficient, there is very much less complexity and far less 

 exuberance of growth. 



In our own woods and forests, the most favoured 

 places seldom possess more than three green layers. 

 There is (i) the tree foliage ; (2) an undergrowth of 

 male and lady fern, with wood flowers such as Hyacinth ; 

 and (3) a carpeting of feathery mosses* (Hylocomium 

 and Hypnum, sp.). 



A very few years ago any scientific person, when let 

 loose in such a botanical paradise as the tropical jungle 

 of West Africa or Java, would do nothing but feverishly 

 collect and dry any flowers that he saw. He would be 

 so entirely occupied, so thoroughly happy in the extra- 

 ordinary profusion of flowers unknown to him, and very 

 likely new species, that he would probably fail to see 

 the " wood " for the trees. 



Even to-day and in Great Britain, there is much to 

 be discovered about the way of life of a "wood" con- 

 sidered as a whole, and not as a catalogue of individual 

 plants. 



Such plants as Foxglove and Raspberry, which spring 

 up in extraordinary profusion when a wood has been 

 felled, may be compared to the seed leaves or cotyledons 

 of a single plant. They are apt to vanish when the wood 

 begins to reform itself. But they are of some use to it, 

 for two or three years' growth of these forerunners cover 

 the soil with rich layers of leaf mould and utilise all the 

 sunshine that falls upon the surface during those years. 



* Five leaf-surfaces are said to exist in many tropical jungles, but the author 

 has seldom seen more than four. Often they are so jumbled up as to be quite 

 indistinguishable. 



24 



