CHAPTER XV 
THE FLOWER OF THE HIGHER SEED-PLANTS 
175. Organs of the Flower. 
— The parts usually found 
in a flower of the higher 
seed-plants are sepals, petals, 
stamens, and pistils (Fig. 97). 
The sepals, taken together, 
constitute the calyx; the 
petals, taken together, con- 
stitute the corolla. The calyx 
and corolla are collectively 
known as the floral envelopes 
Fic. 97. The Parts of the Flower. 
eal, calyx ; cor, corolla; sf, stamens; . 
nee or perianth, 
p, pistil. : “ 
Many flowers consist of 
five whorls or circles, two of which belong to the perianth, 
Fic. 98. Flower of Stonecrop. 
J, entire flower (magnified). II, vertical section (magnified). 
two to the stamens, and one to the pistils. The parts of each 
whorl alternate in position with those of the preceding or 
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