WHAT ARE SOME EXAMPLES OF SPERMATOPHYTES ? 207 



If we summarize the facts we already know about flowering 

 plants, they are briefly these : Seeds, which are formed in the 

 fruits as the result of pollination and later fertilization, give rise 

 under favorable conditions to young seedlings. The conditions 

 which waken the embryo within the seed to activity and growth 

 are favorable conditions of moisture, temperature, air, and food 

 materials. We have learned that under favorable conditions the 

 young plant grows into an adult and in course of time produces 

 flowers. The flower is really a modified branch which contains 

 the male and female gametophytes of the flowering plant. The 

 female gametophyte is contained within the ovary of the flower 

 and is called the ovule. The male gametophytes are the pollen 

 grains which contain the sperm cells. 



Botanists have shown that in the flowering plants or spermato- 

 phytes there exists an alternation of generations, as in the mosses 

 and ferns. The pollen grain is believed to be a spore, which 

 develops into the male gametophyte (the pollen tube), while the 

 embryo sac in the ovary of the flower is another spore, within 

 which is found the female gametophyte. Most of the life of the 

 flowering plant is passed evidently in the asexual or sporophyte 

 stage. 



SPERMATOPHYTA 



Gymnos^ermae — / \ An^ibspermae 



^fonoCot^ledoncteX L DicoWlecfoncte 



evergreen, plctnbs floral part?, 5k — parts ,41? wS$ 



The flowering plants are further divided into monocotyledons 

 and dicotyledons. A brief description of a few of the most im- 

 portant families of these plants is given. These particular ones 

 were selected because they are likely to be seen by the average 

 boy or girl who takes field excursions or hikes. The total number 

 of known species of plants of these groups is more than 240,000. 



