THE FLOWER 217 



Sometimes the sepals and petals may differ one from the 

 other in their appearance, but the leaves comjjosing these two 

 envelopes are spirally arranged, and gradually p;iss over from 

 one condition into the other, as is the case in the Water-lily 

 {Nymphwa), the Queen of the Night (Cereus), and the All- 

 spice (Calycanfhus). 



Sometimes the petals are much reduced or transformed into 

 special organs for attracting insects by the secretion of honey, 

 and are then termed neetapies. In either case the calyx 

 will then undertake the functions of the corolla, and will 

 become brightly coloured, as, for instance, in the Larkspur 

 (Delphinium) and the Monkshood (Aconihim), 



In some cases we find the food material available for the 

 development of the flowers is differently utilised in different 

 flowers of the same species. The female flowers, which re- 

 quire a large amount of nitrogenous food material for the 

 formation and development of their ovules, only produce a 

 very small and inconspicuous corolla, while the male flowers 

 use the food material for the development of a comparatively 

 large and corolla-like perianth, as may be seen in the case of 

 the Hemp. 



On the other hand, we find occasionally a tendency in some 

 plants to produce a more elaborate corolla than is normally 

 formed. In such cases, at the point where the petal or tlie 

 perianth-leaf narrows down into a stalk, there will be pro- 

 duced on the inner surface of the corolla outgrowths of the 

 same texture and colour as the corolla, which form what is 

 termed the paraeoroUa or eopona. The Pheasant's-eye Nar- 

 cissus possesses a structure of this nature of a delicate red 

 colour, while in the Daffodil or Lent-lily it is larger, bell- 

 shaped, and more like the corolla in colour. 



The thousands of variations which may occur in the form 

 and colour of flowers do not change the general conception of 

 a flower which we have put forward, namely, that the flower 

 is a modified shoot, the different leaves of which may become 

 transformed from one series of forms into another. It is the 

 business of the horticulturist to change the nature of the 

 floral leaves to suit his special purposes. 



