CLASS SYNGENESIA. 255 



Frustranea. 



The Third Order has the disk florets perfect ; those of the 

 ray are neutral, having neither stamens nor styles, though an 

 imperfect seed is sometimes seen at the base of the florets ; the 

 name Frustranea alludes to this imperfect seed. We find here 

 the SUN -flower (HELIANTHUS) ; this is a very good plant to 

 examine, as the organs are large, and develope very clearly the 

 peculiar character of the class Syngenesia. 



fig. 121, a, represents the flower of the Coreopsis; b a floret 

 of the disk, with its bifid stigma above the tube, formed by the 

 united anthers ; c shows a ray floret, which is neutral. 



In this order is the CENTAUREA benedicta, or blessed thistle, a 

 native of Spain, which received its name on account of some 

 extraordinary virtues which it was thought to possess, such as 

 being a remedy for the plague, with which warm countries are 

 often afflicted ; at present this plant is, not much valued. 



Necessaria. 



The Fourth Order includes plants in which the rays only 

 are fertile or pistillate, and the disk florets are barren or sta- 

 minate. We find here the marygold (CALENDULA). 



Segregata. 



The Fifth Order contains a few genera, with each floret hav- 

 ing a calyx proper to itself, besides a common calyx including 

 the whole of the florets which make up the flower ; this may 

 be called a doubly compound flower. The only plant of this 

 order yet discovered in the United States is the elephant's-foot 

 (ELEPHANTOPUS), a low, hairy leaved plant ; with purple, ligu- 

 late florets. 



We have now completed a survey of the orders of the class 

 Syngenesia ; the plants which it contains are almost wholly 

 referred to the natural order Compositse or compound flowers ; 

 by Jussieu, they are subdivided into three orders. 



Divisions of Compound Flowers by Jussieu. 



1st, with florets all ligulate and perfect, leaves alternate, hav- 

 ing milky juice, corollas mostly yellow , this includes the dan- 

 delion and lettuce. 



2d order includes all compound flowers with tubular corollas, 

 with receptacles fleshy and chaffy, egret stiff and bristly, leaves 

 often with fwvrsh prickles, flowers in a head ; this includes the 

 thistle, burdock, and false saffron. 



3d order includes such compound flowers as have their inflo- 



Order Frustranea Sun-flower- Explain Fig. 120 Blessed thistle Order 

 Necessaria Order Segregate, Elephant's foot Order Composite Jussieu's 

 division of compound flowers. 



