47 



slightly altered in character in which case it is called a bract. 

 The green sepals are often large and obviously leaf-like ; the 

 petals also in shape more or less resemble leaves and they often 

 have a distinct venation. Colour alone is a characteristic of 

 very little importance in enabling us to decide on the true 

 nature of a member, as is shown by the fact that the bracts of 

 several plants, although they are obviously leaves, are 

 brilliantly coloured like petals, e.g. the bracts of Bougainvillea. 

 The remarkably conspicuous pure white, or coloured, calyx 

 lobe of Mussaenda should also be noted. Stamens it is true do 

 not at first sight at all remind us of leaves, but in some 

 flowers, especially in those which have numerous petals, as in 

 the Water Lily (Nymphaea), we find that the petals gradually 

 pass into the stamens through a series of intermediate forms, 

 which clearly indicate how one and the same organ may, by 

 a number of slight modifications, become a normal, more or 

 less leaf-like, petal, or a perfect stamen. 



The pistil also does not at first sight resemble a leaf, but if 

 we take a simple pistil such as a young pea-pod, and compare 

 it with an involutely-folded leaf, the margins of which are 

 brought together and made to cohere, we see that very slight 

 modifications would, after all, suffice to convert what would 

 ordinarily develop into a normal leaf into a pistil. 



Occasionally also, e.g. in Roses, examples may be found of 

 so-called "green-flowers," in which the different members, 

 instead of assuming their ordinary shape and colour, appear as 

 more or less perfectly developed green leaves. The facts noted 

 above which indicate the true nature of the floral members are 

 found to be confirmed by a microscopic examination of their 

 mode of origin, minute structure and development during the 

 early stages of their growth, when they are found to be 

 indistinguishable from true leaves. The floral parts arise on 

 the flower stalk just as leaves do, on an ordinary shoot. Occa- 

 sionally they are in spirals, but as a rule they are arranged in 

 whorls. The internodes in the flower usually remain very short, 

 and all the floral parts are therefore crowded close together on 

 the portion of the shoot from which they spring, i.e. on the 

 so-called receptacle, or torus. This, however, is not always the 

 case, and in Capparis there is a distinct internode between the 

 stamens and the pistil, the latter appearing to have a stalk 

 which is called the gynophore ; internodes are also occasionally 

 developed between other floral parts, e.g. between the petals and 

 stamens in species of Grewia, and a stalk which thus appears 

 to bear both the stamens and the pistil is called a gonophore. 



