160 ORGANIC METAMORPHOSIS OF LEAVES 



tween petals and stamens, may be obtained in many 

 flowers, especially in the common spatterdock of the 

 pools (Nuphar advena), and the white water lily [NymphoBa 

 alba). These terms may furnish the botanist with conve- 

 nient artificial distinctions, which are very available in 

 botanical diagnosis ; but absolute boundaries between 

 sepals, petals, stamens, and pistils, do not exist in [N'ature ; 

 there is the utmost latitude and freedom of form, and we 

 seek in vain to confine her in the fetters of an artificial 

 nomenclature. 



Examine the flowers of the yellow lily oi- spatterdock, 

 and you will find that the sepals or leaves of the calyx, 

 although green externally, are yellow internally, and thus 

 approximate in appearance to the petals ; that the petals, 

 which are arranged in a closely-approximated spiral, 

 gradually become smaller as they are more centrally situ- 

 ated ; for the anthers become visible on their upper side, 

 and the lower portion of the petal contracts into a filament. 

 The curious pollen-bearing leaves, called stamens, are 

 thus identified as metamorphosed petals ; for such tran- 

 sitional forms remove every shadow of doubt from the 

 mind. 



In the pistil or central organ of the flower, there appears 

 to be the greatest departure from the primitive leaf-type ; 

 yet it is not difficult to trace it even in this instance. The 

 analogy of the pistil to the leaves is easily demonstrated 

 in the flower of the Ii-is, the pistils of which are petaloid, 

 or petal-like. In general, the pistil is nothing but a leaf 

 which remains folded on its midrib, the two sides of the 

 lamina continuing together instead of separating, as in 

 ordinary cases. Whilst in this condition, the margins of 

 the lamina anastomose, or grow together, and thus form a 

 placenta or point of attachment for the ovules in its inte- 

 rior. The folded condition of the leaf in the young state 

 may be observed in the leaves of the Cherry tree and com- 

 mon Garden Rose. Examples, too, are not uncommon of 

 the development of stunted green leaves in the centre of 

 the flower, in the place of the pistils, as in the Double 



