94 GLEANINGS FROM NATUliE. 



start in life. They radiate in all directions from the 

 base of the stem, spreading over an area of several 

 square yards and penetrating the soil in search 1 of 

 moisture to such a depth as to render abortive any 

 attempt of man to pull the plant up bodily, roots and 

 all. In rich soil the stem grows to a height of six to 

 eight feet and is leafy to the top. The leaves are 

 linear to lanceolate-oblong in shape, sbarply toothed, 

 and so innutritions that none of the higher animals, 

 not even the sheep, will feed upon them. 



The only insect enemies of the plant, so far as noticed, 

 are the black blister beetle which attacks the leaves 

 when other food is scarce, and a small gall fly whose 

 larvae feed upon the juices of the flowering branches. 



Many species of bumble-bees and butterflies visit its 

 blossoms in search of nectar and pollen, and thus aid 

 materially in their fertilization. The flowers in each 

 head number, on an average, twenty -five, each of 

 which produces a single seed. On one specimen of 

 medium size were counted 743 heads, so that 18,575 

 seeds, each capable of becoming a fully developed 

 iron-weed, were borne by that plant alone, and the 

 majority produce as many, or more. To secure a 

 broad dissemination each of these seeds bears at matu- 

 rity a tuft of light brown bristles known as the pap- 

 pus, and by its aid the seed may be wafted .by the wind 

 miles away from the parent plant. Again, an the 

 iron-weed grows in greatest luxuriance in the lowland 

 pastures near small streams, many of the seeds fall 

 upon the water and are borne onward till they lodge 

 against some bank or are buried in the sediment 

 deposited by an overflow; places well suited tor their 



