Thistles

Genus Cirsium
Aster Family (Asteraceae/Compositae)






Thistles
(Cirsium spp.)

Thistles have wavy or toothed leaves, and each tooth has a sharp spine at the tip. Usually there are also spines and prickles on the stems and branches. The color of thistle flower heads can vary quite widely, through various shades of purple and lavender, to nearly white.



An unknown species of thistle
   in Butterfield Canyon -- Oquirrh Mountains

A thistle growing in Red Butte Canyon -- Wasatch foothills





Some species are native to this area, but many others have been introduced.

Some non-native thistles now common in Utah:
  Bull Thistle (Cirsium vulgare)
  Canadian Thistle (Cirsium arvense)
The photos on this page are probably either Canadian Thistles or Bull Thistles. Both of these species have branched stems with a flower head at the top of each branch.

Another non-native thistle, of a different genus, is shown here:
  Musk Thistle (Carduus nutans)




See some native thistles found in the mountains:
    Mountain Thistle (Cirsium eatonii
Elk Thistle (Cirsium foliosum)





Oquirrh Mountains and
Wasatch Mountains
Salt Lake County, Utah

References


Photographed
by Sandra Bray