126 



INTRODUCTION TO BOTANY 



tarn 



A, entire flower, B, lengthwise section ; carp, 

 carpels; stem, stamens; pet, petals; sep, sepals, 



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 is, 



to the root, the stem, 



P** and the leaf. There 



is, however, plenty of 

 evidence to show that 

 the flower is a much- 

 shortened and other- 

 wise modified branch, 



FIG. 102. Flower of live-forever (Sedum) Specialized for the pro- 



duction of seed. The 

 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 .-. ,. , 



all separate. Somewhat enlarged. After Schimper One ot 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, 

 the receptacle is but little enlarged ; 



FIG. 103. Lengthwise section 

 of flower of a buttercup 



-inn , car P, carpels; pet, petal; sep, 



Sometimes, as in figure 103, it IS sep al; rec, large convex recep- 



much enlarged ; often it is convex tacie on which the numerous 



TT ,, . ,. , carpels are borne. Somewhat 

 Or concave. Usually in dlCOtyle- 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 



