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enable the tree to adapt itself to these special shapes ; but 

 everybody knows that the contributory cause of the shapes 

 is the gardener. 



Similarly with regard to our ferns. It has often occurred 

 to me that the power to form varieties may be awakened 

 and stimulated by the circumstances in which the fern 

 grows. For instance, when we search for ferns along a 

 hollow ditch, where the ferns have to push upwards, as 

 best they can, among thick brambles, we are sure to find 

 many abnormal forms. Of course the majority of these forms 

 arise immediately from the way in which the fronds have 

 to work their way in and out of the obstructions, and 

 doubtless if the brambles were removed there would be 

 return, in most cases, to the type. 



Is it not, however, probable that a fern, which has for 

 many years developed in difficulties which interfered with 

 the proper expansion of its fronds, should gradually so 

 adapt itself to its environment as to perpetuate the form 

 which circumstances have imposed ? 



Another illustration of a totally different character 

 presents itself when ferns have found for themselves a 

 situation exceptionally favourable. Recently I came across 

 specimens oi poly podium vulgave, so delightfully posed upon 

 the side of a steep shady bank beside a tiny waterfall, that 

 they had grown and grown until at least twice the normal 

 size, and had assumed in their pinnae a rich and sinuous 

 appearance, which bade fair for an early break into 

 vigorous plumose form. 



More remarkable, in my opinion, than either of the 

 instances already given, is the way in which I have found 

 Blechmtm Spicant, on two recent occasions, adapting itself, 

 in different places, to similar surroundings. In both cases 

 the caudex of the fern was deeply set in the interstices of a 

 dyke built of loose stones and clay. Before the fronds 

 could expand normally they had to work outwards in some 

 cases as much as nine inches, in order to be free from the 

 stones which pressed them on each side. The fronds 



