152 1 INN/VAN ARTIFICIAL SYSTEM. 



126. Polygamia necessaria : In this order, the florets 

 of the centre are furnished with stamens only, while 

 those of the margin or circumference, are merely sup- 

 plied with pistils. The presence of both kind of florets, 

 are therefore necessary for the production of seed. 



The family calendula or marygold, of which the common variety 

 in our gardens is a native of the south of Europe, belongs to this 

 order. The three Cape genera, othonna or rag-wort, osteospermum, 

 and arctotis, are likewise of this division. 



127. Polygamia segregata : This order of the class 

 syngenesia, embraces snch plants as bear several flowers, 

 either simple or compound, but with united tubular 

 anthers, and with a partial calyx, all included in one 

 general calyx. 



We have examples of this order of plants, in the genera echinops 

 or globe-thistle, elephantopus or elephant's-foot, and a few others. 



CLASS XX. GYNANDRIA. 



128. Character : The plants of this class are 

 furnished with perfect flowers, the stamens of which are 

 inserted either upon the style or germen of the pistil. 

 (F. 192.) 



This is rather a miscellaneous class of plants. Linnnus, how- 

 ever, deemed the first order, which he called diandria, as a natural 

 assemblage. They constitute his seventeenth order narnrd orchiiieee. 

 Many plants which were previously arranged in this class, are now 

 removed to other divisions of the system. 



129. Ditision .-Botanists are very uncertain about 

 the correct number of orders, which bhould form Um 



