THE IRON-WEED. 



Belonging to the great. Composite family of plants 

 are many of our worst weeds, such as the rag-weed, 

 horse-weed, white-top, thistle, burdock, and last but 

 not least, that scourge of our blue-grass pastures 

 the iron-weed. The name, Composites, is given to the 

 family from the fact that its members have their 

 small, yet perfect flowers densely crowded together 

 into a head, which is enclosed by an involucre or cup 

 formed of several circles of modified leaves called 

 "bracts"; this involucre performing the same pro- 

 tective function for the compound mass that the calyx 

 or outer green envelope does for the ordinary sepa- 

 rate flowers of other families. The object of this 

 massing together of a great number of. small flowers 

 into a large head is that they may more easily and 

 certainly attract the attention of insects and thus 

 secure their fertilization. Taken singly, the flowers 

 are too small and inconspicuous to attract separate 

 attention, but by huddling themselves together into a 

 showy mass they have proven themselves very suc- 

 cessful plants ; so much so, indeed, that the family is 

 now the largest known in the vegetable world. 



Many of the Compositce, as the sunflowers and asters, 

 have the outer flowers of the head enlarged into the 

 so-called " rays," thus increasing their showiness, while 



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