54 FARM WEEDS OP CANADA 



RUSSIAN THISTLE (Salsola Kali L. var. ienmfolia G.F.W. Mey.). 



Other English names: Russian Tumbleweed, Russian Cactus. 



Other Latin nsunes: Salsola Tragus L., Salsola Kali var. Tragus 

 Mog. 



Introduced from Asia. Annual. Bushy, of a prickly ap- 

 pearance, due to the long, thin, thread-like, prickle-tipped leaves 

 which characterize the young plant, and the short, triple, spiny 

 bracts on the flowering branches of the older plants. It varies 

 in appearance at different stages of growth. The young plant 

 is dark green; the slender leaves, about two inches long, drop 

 off soon after the seed is formed. The somewhat spherical 

 branched top of the mature plant, when broken away from the 

 root, is blown about by the wind and scatters its seeds widely. 

 It is not a thistle and could be more appropriately called a tum- 

 bleweed. Flowers solitary, borne in the axils of the leaves. 



The seed (Plate 72, fig. 13) is about 1/16 of an inch in di- 

 ameter, cone-shaped, the large end concave with a well marked 

 protuberance in the centre of the cavity. The coat is thin 

 and transparent, showing the grayish-brown, coiled germ. It 

 is generally enclosed in a papery envelope, the divisions of which 

 are winglike and help to disseminate the seed. 



Time of flowering: July to September; seeds ripe by August. 



Propagation: By seeds. The seeds are distributed by the 

 tumbling plants, which are driven by the wind. As the seeds 

 do not shell readily, they are carried long distances. 



Occurrence: Abundant in several localities in the dryer 

 parts of southern Alberta and Saskatchewan, chiefly along 

 roadsides, fire-guards and in neglected fields. Frequently found, 

 though not seriously troublesome, in the eastern provinces. 



Injury : Russian Thistle is a large, succulent weed and 

 thrives where the land is too dry for other plants. It thus uses 

 up moisture where it is, scarcest and most needed. Owing to 



