THE BOOK OF NATURE STUDY 



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to the light. This is well seen in some of the plants now so 

 commonly sold by florists. The Eucalyptus is an example of this, 

 as is also the Acacia, though in the latter plant the "leaves" are 

 really flattened leaf stalks. On the other hand, the majority of 

 plants spread out their leaf-blades to the light, which is far less in- 

 tense in our own climate. Again, Alpine plants like those found on 

 the tops of the highest Scotch mountains, such as Ben Lawers, are 

 often of much smaller growth, with small hairy leaves in rosettes, 

 because in these high altitudes, owing to the special conditions of 

 temperature and wind, it is important that the plant should give 

 out as little water as possible, and the leaf surface is therefore 

 considerably reduced, or very hairy. Plants of this kind are to 

 be found even on hills not more than 800 feet high. The Stork's 

 Bill, the Field Alchemil, the Alpine Pennycress may be mentioned. 

 The leaves of water plants, as every one knows, are very different 

 from those of land plants. Some have long, ribbon-like leaves, 

 which can stand floods better than any other shape ; others have 

 leaves adapted for floating, whilst a third set of water plants 

 have leaves able to live and do their work entirely under water. 

 In plant life, too, there are quite as many interesting biological 

 problems to be solved as in animal life. The phenomena of the 

 distribution of plants offer a wide field to the speculative botanist. 

 No satisfactory explanation of the flora of certain areas is as yet 

 forthcoming. There is a district in Gloucestershire, which shall 

 be nameless, as there are some rare plants in it, where certain 

 species not present anywhere else in the county are to be found. 

 How did they get there ? Supposing that the answer is, that 

 certain seeds are carried long distances by the wind, still the 

 puzzle remains : Why have these plants established themselves 

 just in this small area and nowhere else in the county ? What 

 conditions, or combination of circumstances, obtain there, and just 

 there alone, that are absent in the immediate neighbourhood ? 

 Or, to take another biological problem. There is abundant 

 evidence of a struggle for existence going on between plants. This 

 is being more and more realised, now that vegetation maps are 

 being drawn in many parts. On certain Yorkshire moors, the 

 bilberry is struggling with the cotton-grass. Where the moor is 

 windswept and drier, the bilberry ousts the cotton-grass and 



