Cirsium arvense

Common Name: 
Canada thistle, creeping thistle
Scientific Name: 
Cirsium arvense (L.) Scop    syn.  Carduus arvensis
Family Name: 
Asteraceae (Compositae) - Aster or Sunflower Family
Identification Notes
Life Cycle
introduced perennial, reproducing by seed and creeping roots
Stems
upright, tall, branched above, ridged
Stems of Canada Thistle
Leaves
alternate, oblong to lance-shaped, sessile, crinkly margins, lobes irregular and spiny
Leaves of Canada Thistle
Leaves of Canada Thistle
Leaves of Canada Thistle
Flowers
heads of rose-purple (sometimes white) disk (tubulate) florets; spineless bracts; terminal and axillary above; dioecious
Flowers of Canada Thistle
Flowers of Canada Thistle
Flowers of Canada Thistle
Flowers of Canada Thistle