100 Elementary Botany 



CHAPTER X. 



STRUCTURE AND FUNCTIONS OF PARTS OP THE 

 FLOWER. 



The flower is that part of the plant which Sulserves the pur- 

 poses of reproduction. 



When complete, the flower consists of four whorls or series 

 of organs. The two outer ones are merely coverings, whilst 

 the inner ones form the essential organs. 



Commencing at the exterior, the outer coat is known as the 

 calyx (fig. 159, k), and each division of which it is made up 

 is a sepal. The inner coat is the 

 -B coroUa (fig. 159, b), and each sepa- 

 rate part of it a petal. 



If both coats be present, as in 

 the Buttercup, the flower is said to 

 be dichlamydeous ; if only one, as 

 in the Anemone, monochlamydeous ; 

 if both be absent, as in the Ash, 

 achlamydeous. 

 ,_. , . The outermost whorl of the es- 



FlG. i5g.—Flovrerot Stsymdrium 



Aiiiaria: K, calyx.; h,coioUa.; scntial orgaus of the flower is the 



s, stamens ; st, pistil. ... , ... 



androecium (fig. 159, s), consistmg 

 of one or more stamens ; whilst within there is the pistil or 

 gynoecium (fig. 159, s^), consisting of one or more carpels. 



This will be a convenient place to note the distinction that 

 is drawn between a complete and a perfect flower. 



For a flower to be complete, all four of the whorls must be 

 present ; if any one be absent, the flower is incomplete. On 

 the other hand, the term perfect is applied to all those flowers 

 in which both androecium and pistil are present, although, as 

 in the Anemone, one of the coats may be wanting, or even, as 



