Unopened Flower Head Side
West Block, Cypress Hills Provincial Park
I find the key answers separating C. undulatum from C. flodmanii to be contradictory and not always correct. Therefore, rather than trying to consolidate the answers from the different flora I have simply reprinted them verbatim. The viewer can compare the answers with the pictures on this site and draw his/her own conclusions. I find the best way to separate the two species is:
C. flodmanii occasionally has entire-margined lower leaves. C. undulatum never does. Thus the presence of entire margined leaves is sufficient to identify C. flodmanii, but the absence is inconclusive.
The achene of C. flodmanii is brown and has a well-defined yellow apical band about 0.5 mm wide, while the achene of C. undulatum is more straw coloured and does not have a well-defined apical band. Compare the achenes of the two species on this web site.
Undulatum: Answers to key questions in Budd's Flora (BF) and Flora of Alberta (FOA) leading to this species. Also included are just those answers from the species key in Flora of the Great Plains (FGP) which separate C. undulatum from C. flodmanii. All the answers which separate C. undulatum from C. flodmanii are written on a white background.
Cirsium: Answers to key questions in Budd's Flora (BF) and Flora of Alberta (FOA) leading to this genus.