CHAPTER XVI 
TRUE NATURE OF FLORAL ORGANS; DETAILS OF 
THEIR STRUCTURE; FERTILIZATION 
221. The Flower a Shortened and greatly Modified 
Branch. — In Chapter VIII, the leaf-bud was explained 
as being an undeveloped branch, which in its growth 
would develop into a real branch (or a prolongation of 
the main stem). Now, since flower-buds appear regularly 
AU PALE SWS 2 
Fig. 158. — Transition from Bracts to Sepals in a Cactus Flower. 
either in the axils of leaves or as terminal buds, there is 
reason to regard them as of similar nature to leaf-buds. 
This would imply that the receptacle corresponds to the 
axis of the bud shown in Fig. 86, and that the parts of 
the flower correspond to leaves. There is plenty of evi- 
dence that this is really true. Sepals frequently look 
very much like leaves, and in many cacti the bracts 
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