76 AN INTRODUCTION TO THE STUDY OF FOSSILS 



the Flowering Plants (Fig. 27). The typical flower is com- 

 posed of (i) a covering, the perianth, which may consist of an 

 outer bud-covering portion, the calyx, and an inner colored 

 portion, the corolla. The entire perianth may be brightly 

 colored or uncolored. Within the perianth are (2) the male 



Fig. 27. — Fossil flowers, because of their delicacy, are rarely preserved. A, 

 Carpolithes macrophyllns, from the Miocene shales of Florissant, Colorado. (From 

 Cockerell.) a, entire flower with its four large calyx lobes; b, detail of venation; 

 c, fruit. B, restoration of flower of Combretanthites eocenica, from the Eocene 

 of Tennessee. X 4. (From Berry.) 



organs, — the stamens bearing the pollen, which are the male 

 cells of fertilization. The stamens are arranged in one or more 

 circles ; at their center is (3) the female organ, the pistil, 

 the outer portion of which, the stigma, receives the pollen while 

 the inner portion, the closed ovary, contains the ovules which 

 after fertilization by the pollen become seeds. 



The method of fertilization is somewhat complicated. Each 

 dust-like pollen grain is a single cell with a single nucleus at its 

 center. When this pollen grain is lodged, through the agency 

 of the wind or an insect, against the stigma, the usually sugary 

 solution there holds it and causes it to grow. By this time the 

 single nucleus will have divided into two or three, one of which, 



