120 



BIOLOGY 



FIG. 62. DETAILS OF AN 

 ANTHER OF A FLOWER 



A, section across the anthers, 

 showing the foiw cavities with the 

 pollen, p, enclosed; B and C, pollen 

 grains; n, nucleus; sp, the pollen cell 

 or microspore. 



others some of the stamens disap- 

 pear. Some flowers are entirely 

 without stamens and are spoken 

 of as imperfect flowers. 



Carpels. Within the stamens is 

 the fourth and last row of leaves. 

 In this case the parts have lost all 

 resemblance to leaves and in ordi- 

 nary flowers they would never be 

 thought of as corresponding to 

 leaves, unless carefully examined. 

 The parts of this inner row are 

 known as carpels (Gr. carpos = 

 fruit); Fig. 60 car. Each carpel 

 consists of three portions, a lower, 

 somewhat expanded portion known 

 as the ovary (Fig. 63 ov), and above 

 this a more or less elongated, slen- 

 der part, called the style, s, whose 

 upper, slightly roughened surface 

 is known as the stigma, st. These 

 three parts form what is commonly 

 called the pistil. It frequently 

 happens that the number of car- 

 pels is less than that of the calyx, 

 corolla, or stamens. Moreover, the 

 carpels are often so fused together 

 that it is impossible to count dis- 

 tinctly the separate carpels of which 

 it is composed. When this occurs, 

 there is found in the center of the 

 flower what is known as a com- 

 pound pistil, i. e., a pistil made of 

 several carpels fused together; see 

 Fig. 63 B. But it is usually 



A B 



FIG. 63. PISTILS 



A, a pistil made up of a single 



carpel; B, a compound pistil ma 

 up of three carpels; s, the style; si, 

 the stigma; ov, the ovary. 



