
THE FLOWER 205 
used is to cut off a portion of a stem, known as a cutting, and 
plant it in the ground. Under favorable conditions the cutting 
produces roots and leaves and grows into a new plant. In a 
few instances leaves of plants may fall to the ground and grow 
into new plants, as in Bryophyllum (Fig. 83) and Begonia. A 
considerable number of plants can be artificially reproduced by 
the use of leaf cuttings. Some ferns reproduce regularly by 
having the tip of a long leaf reach the ground, send out roots, 
and grow into a new plant (Fig. 82). 
Sexual reproduction. Sexual reproduction is reproduction in 
which two cells unite to form a single one from which a daughter 
organism develops. This method of reproduction is character- 
istic of the vast majority of plants. Among the higher plants 
the flower is the organ for sexual reproduction. 
THE STRUCTURE OF THE FLOWER 
Parts of the flower. In a complete flower, that is, one which 
has all the parts of a typical flower, there are four kinds of 
structures besides the stalk (Figs. 202, 203). There are one 
or more prstils, stamens, a calyx, and 
a corolla. The pistils and stamens are 
the essential parts, while the others are 
accessory. 
Some flowers are regular, — that is, 
all the members of each set of organs 
are alike (Figs. 202, 210-213), — while 
others are irregular (Fig. 204). 
Pistils. ‘The pistils are usually found 
in the center of the flower (Fig. 203). 
A pistil consists of an enlarged basal 
portion called the ovary; a terminal part known as the stigma ; 
and, usually, a long, slender structure, the style, which connects 
the ovary with the stigma. The ovary contains one or more cavi- 
ties (Fig. 205) within which are found small oval or egg-shaped 
ovules. An ovule is attached to the ovary wall by a small stalk 

Fig. 202. Flower of Mun- 
tingia calabura. (x 14) 
