126 INTRODUCTION TO BOTANY 
115. What is a flower? A hasty examination of an ordinary 
flower does not give much evidence as to the relation which its 
organs bear to the parts of the plant already studied; that 1s, 
to the root, the stem, 
and the leaf. There 
is, however, plenty of 
evidence to show that 
the flower is a much- 
shortened and other- 
wise modified branch, 
specialized for the pro- 
; ; ; duction of seed. The 
_1, entire flower, B, lengthwise section ; carp, 
carpels; stam, stamens; pet, petals; sep, sepals. floral organs therefore 
An excellent example of a flower in which the correspond to leaves. 
parts of each circle are of the same number and Pi; al 
all separate. Somewhat enlarged. After Schimper One of the most easily 
understood evidences 
of the branch-like character of the flower is the fact that 
the positions of the flower buds on the branch are similar to 
those of leaf buds; that is, they are usually either axillary or 
terminal. Moreover, in its earliest 
stages a flower bud’ is developed 
much as a leaf bud is. 
116. The arrangement of the 
organs of the flower. The floral 
organs spring from the receptacle, 
an expanded portion of the flower ; 
stalk. Sometimes, as in figure 102, Fic. 103. Lengthwise section 
, f of flower of a buttercup 
the receptacle is but little enlarged ; 
; . Se awe OS. ae 4 carp, carpels; pet, petal; sep, 
sometimes, as in figure » It 18 sepal; ree, large convex recep- 
much enlarged; often it is convex tacle on which the numerous 
U ile tn dideiol earpels are borne. Somewhat 
or concave. SUidteye Ul CHeOuy4e= enlarged. After Baillon 
dons the floral organs are arranged 
in whorls, or cycles (that is, in circular fashion), on the recep- 
tacle, but sometimes part or all of them are in spirals. In case 
there is the same number of parts in each cycle, each part 
commonly stands opposite a space between two members of the 
Fic. 102. Flower of live-forever (Sedum) 
