Canada Thistle (Cirsium arvense) (European) is a 
small flowered, perennial species that has strayed across 
the ocean and became a pernicious weed. 
The stem is rather slender, branching and grows from 
1 to 3 feet in height. It grows from a perennial, creep¬ 
ing rootstalk that is, as farmers have discovered, very 
difficult to eradicate from the soil. It grows in ex¬ 
tensive colonies and, unless strenuous efforts are made to 
destroy them, they very soon take possession of a field 
to the exclusion of almost everything else. 
The leaves, that grow alternately and closely together 
on the stem, are long, lance-shaped, deeply cut into 
sharply-prickled lobes. Numerous flower heads, about 
one inch across, terminate the branches. When in full 
bloom, the florets vary in color from rose-purple to 
white; the involucre is almost globular and covered 
with over-lapping bracts, each with a tiny, sharp, out- 
turned point. 
All the thistles yield an abundance of nectar and are 
frequented by bees and butterflies. 
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