Il8 CLASSIFICATION OF PLANTS 



of the group is the pistil, a megasporophyll so formed as to 

 entirely enclose the megasporangia. The flower consists of 

 several circles of sporophylls surrounded by several circles of 

 specially modified floral leaves. All these leaves are set close 

 together on an extremely short axis. The typical flower bears 

 at its apex or centre a circle of megasporophylls, around this 

 two circles of microsporophylls and around these again two 

 circles of floral leaves. Both circles of floral leaves may be 

 colored or only the inner one. 



299. The male gametophyte is represented only by a single 

 pollen tube nucleus and a sperm mother nucleus which divides 

 into two sperm nuclei. No division into cells occurs. The 

 female gametophyte is represented by the endosperm and the 

 archegonium by the egg apparatus (two synergids and the egg 

 cell). 



300. The first seven orders of Angiosperms are Monocoty- 

 ledonous (see page 71). The Dicotyledons contain thirty- 

 three orders. 



301. For a detailed description of flowering plants the student 

 should consult a manual of botany. 



