54 BIOLOGY AND HUMAN LIFE 



There has been developing an interest in propagating wild 

 flowers by means of seeds planted in suitable places. Protected 

 from careless pleasure seekers, plants can in this way be made 

 to cover unused spots, and some of the rarer varieties may be 

 preserved from extermination. This seems to be a good plan to 

 follow in many parts of the country, and is worth helping. 



THE CYCLE OF LIFE: FLOWERS 



1. Reproduction (what it means) 



Related to the beginning of life 

 Related to the end of life 



2. Structure of flowers 



The floral envelope 



The calyx — (sepals) ; the corolla — (petals) 

 Essential organs 



Stamens Carpels — (pistil) 



Anther — (pollen) Ovary — (ovule) 



Filament Stigma 



Style 



3. PoUenation (meaning) 



Close-pollenation and cross-poUenation 

 Agencies of cross-pollenation 

 Wind ; insects ; water ; birds 



4. Origin of new plant 



FertiHzation 



Pollen tube ; embryo sac ; fusion 

 Growth of seed 



Fertilized embryo sac becomes embryo 



Ovule becomes seed 

 Ripening of seed 



Ovary becomes seed-bearer (fruit) 



5. Interdependence between insects and flowers 



6. Homologous parts of flowers 



7. Analogies in composite and other clusters of flowers 



8. Conservation of wild flowers 



Spare ; protect ; propagate 



