288 



CULTURE OF FARM CROPS. 



or plants in which both the corolla and the calyx are pre- 

 sent. The sub-class dichlamydece is again divided into 

 three classes, of which it is necessary here to name only 

 the one to which the turnip belongs, namely, the malami- 

 florce. Of this sub-class all the plants have the petals and 

 the stamen sprung from the receptacle, and are distinct 



Fig. 8. 



from one another, the stamens being what is termed 

 hypogynous, that is, rising from the upper part of the 

 peduncle under the pistils. Of this sub-class, the malami- 

 florce, the " order " cruciferce is that to which the turnip 

 belongs, the " genus " being Brassica. In fig. 9 we give 

 a rough diagram of a cruciferous flower. From the posi- 

 tion of the petals, a b c d ) and from which the name is 

 derived, the petals are always four in number, and opposite 



