W165 



RUSSIAN-THISTLE 



sal sola pes'tifer, syns. S. ka'li tenuifo'lia, "S. ka'li tra'gus", and "S. tra'gus" 1 



Flowers inconspicuous, perfect, 2- 

 bracted, 1 to several in the axils of the 

 ^> spinelike leaves; petals lacking 



Stamens 5 



Outer united flower parts (calyx) 5- 

 parted, up to l / 4 in. broad, papery, with 

 prominent veins, persistent, enlarging 

 and becoming winged 



Seed pod (utricle) flattened top- 

 shaped, enclosed by persistent, winged 

 calyx, tipped by 2 persistent, thread- 

 like stalks (styles), 1-seeded; embryo 

 spirally coiled 



Leaves about 2% in. long, somewhat 

 fleshy, needle-shaped, spine-tipped, be- 

 coming dry and stiff 



Stems profusely branched, forming a 

 bushlike growth up to 4 ft. high and 6 

 ft. across, stout, hairless, green, be- 

 coming red with age, parallel-ribbed, 

 arising from an annual taproot 



Russian-thistle, one of the numerous annual plants known as tumbleweed, 

 is actually not a thistle but a member of the goosefoot family (Chenopodi- 

 aceae), closely related to lambsguarters, saltbushes, and the cultivated beet 

 and spinach. Russian-thistle, a native of Eurasia, was a serious pest in the 

 Russian wheat fields many years before it spread to the United States. This 

 plant was probably introduced into Bon Honime County, S. Dak., in 1886 as an 

 impurity in flaxseed imported from Europe. 2 The few plants produced in- 



1 Of United States authors, not L. 



- Dewey, L. H. THE RUSSIAN THISTLE AND OTHER TROUBLESOME WEEDS IN THE WHEAT 

 REGION OF MINNESOTA AND NORTH AND SOUTH DAKOTA. U. S. Dept. Agr. Farmers' Bull. 



10, 16 pp., illus. 1893. 



