TKTJB NATUKE OF FLOEAL OEGANS. 



153 



sepals and petals in such flowers as the white water-lily. In 

 this flower there is a remarkable series of intermediate steps 

 ranging all the way from petals, tipped with a bit of anther, 

 through stamens with a broad petal-like filament to regular 

 stamens, as is shown in Fig. 136, E, F, G, H. The same 

 thing is shown in many double roses (Fig. 137). In com- 

 pletely double flowers all the essential organs are transformed 

 by cultivation into petals. In the flowers of the cultivated 

 double cherry the pistils occasionally take the form of small 

 leaves, and some roses turn wholly into green leaves. 



Summing up, then, we know that flowers are altered and 

 shortened branches : (1) because flower-buds have the same 



I n ni IV V VI, 



Fig. 137. — Transitions between Petals and Stamens in a Rose. 



kinds of origin as leaf-buds ; (2) because all the intermediate 

 steps are found between bracts on the one hand and stamens 

 on the other ; (3) because the essential organs are found to 

 be replaced by petals or even by green leaves. 



188, Mode of Formation of Stamens and Pistils frofn 

 Leaves. — It is hardly possible to state, in a book for begin- 

 ners, how stamens stand related to leaves.^ 



The simple pistil or carpel is supposed to be made on the 

 plan of a leaf folded along the midrib until its margins touch, 

 like the cherry leaf in Fig. 61. But the student must not 

 understand by this statement that the little pistil leaf grows 



1 " The anther answers exactly to the spore-cases of the ferns and their allies, 

 while the filament is a small specialized leaf to support it." For a fuller statement, 

 see Potter's Warming's Systematic Botany, pp. 236, 237. 



