thistle

[cohan]

Cohan, I haven't pored over your photos and description in much detail, but I thought I'd just add the following...

-C vulgare is said to have single flower heads per stem, whereas mine had a cluster of three;

Flora of Alberta disagrees, and says of C. vulgare, "heads usually several".  

The F. of A. key also makes the following basic distinction between C. vulgare and the native species - "upper surface of leaves scabrous with appressed spines" (= C. vulgare); "upper surface of leaves not scabrous" (= the 6 native species).  From your photos, the upper leaf surfaces look scabrous (rough) but I may be misled...

I can't say I've studied thistles enough to help out particularly, other than to confirm that it is not C. hookerianum, which I do take note of and always enjoy seeing (see links for photos of it):  
http://nargs.org/smf/index.php?topic=131.30
http://nargs.org/smf/index.php?topic=361.0

thanks lori, my original impressions of numbers of flower heads were from the (as we know) limited royer/dickinson book; looking at eflora of north america, it seems that isn't much of an identifying character for any of the species involved here, at least, almost were, if not generally multiple, then something like  1-10, or 1 or a few, etc....

as far as scabrous, some of these terms seem so relative, its really hard for me to judge some of them having no other thistles to compare to, other than C arvense..i didn't specifically test for roughness of the surface (i may check--there are probably still overwintering rosettes of those that didn't flower).. i know the overall 'feel' of the plant was more downy than prickly, and eflora mentioned vulgare havinga kind of prickle on the upper leaf surfaces, which i don't think i see on my plant, but again, with no sufficiently close images (let alone live plants) of any other thistles to compare to, i sure wouldn't swear to it...

the involucre, however, as i mentioned above, does not look like vulgare at all, and while not as marked on my plant as some images i have seen, the white ridge on the phyllaries which clearly exists on mine, is not supposed to appear on vulgare; nor does the form of the phyllaries on mine--flat to the involucre, tip spines abruptly spreading outward, seem to match descriptions or images of vulgare..but these things are hard to do from photos, i know, and i may be missing something obvious to someone with more thistle experience....

from what i've seen/read if maps and habitat, it didn't seem hookerianum should appear here, but of course maps have been wrong before, however, this plant is in a habitat more woodland, and moist, than anything else...
what are the rest of the 6 native species, out of  curiosity? i didn't find that many species that mention alberta on efloras....
hookerianum, flodmanii, undulatum, drummondii...

[cohan]

ok, of course i didn't get good photos of the involucre and phyllaries, not realising that was important..lol--it may take me several years to get the right images of some plants....
but here is the best i have, the detail on the smaller head is clearer--note the white ridge, dark, bent phyllary tip spine, which as far as i can tell, are not typical of C vulgare..
even clearer than in my photo is this image of C undulatum from saskatchewan -not the same as mine, probably, but similar phyllaries, distinct from vulgare, in the second link...
http://em.ca/garden/native/nat_Cirsium%20undulatum.html
http://www.discoverlife.org/mp/20p?see=I_HLV151&res=640

also a close-up of a cauline leaf of mine, i've been peering at it, and trying to find web images to compare to, but simply can't say if this is what they call 'scabrous with (i assume they mean -due to-) appressed spines' i'd need to see a good image of each to know... leaf texture on mine does not  seem different to me than images online of other natives, but again, i could easily be wrong looking at web pics.....my feeling again, was that this plant is more fuzzy than prickly, but i can't compare it to anything but arvense, which is much pricklier....

[Lori S.]

There's a nice clear photo of the leaves now (your second photo, immediately above).
From eFlora of N. A. (which also says, by the way, "heads many" for C. vulgare):
"Native to Eurasia, Cirsium vulgare is the only thistle in North America with bristlelike spines borne on the adaxial leaf faces. These structures are variously described in the literature as trichomes ("spreading hirsute," "scabrous-hispid," "coarsely hispid," "rigid, rather pungent setae," "prickly-hairy"), prickles, or spines ("setose-spinulose," "appressed and dense spines")."
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200023702

"Adaxial" leaf surfaces = upper leaf surfaces

I dunno... as I said in the disclaimer  , I don't know much about thistles... but, based on the above (which corroborates the F. of A. key),  I think your thistle is pointing to C. vulgare... ?

Here's a closeup of the lower leaves of C. hookerianum, for comparison... said not to be scabrous, lacking appressed spines, in F. of A..   I think this photo shows a clear difference, which may be what the F. of A. key was trying to get across.  The leaves near the inflorescence on C. hookerianum become woolly, with tangled hairs, but not spiny (second photo).

Oh, and the other 2 native thistles are C. foliosum and C. scariosum.

[cohan]

There's a nice clear photo of the leaves now (your second photo, immediately above).
From eFlora of N. A. (which also says, by the way, "heads many" for C. vulgare):
"Native to Eurasia, Cirsium vulgare is the only thistle in North America with bristlelike spines borne on the adaxial leaf faces. These structures are variously described in the literature as trichomes ("spreading hirsute," "scabrous-hispid," "coarsely hispid," "rigid, rather pungent setae," "prickly-hairy"), prickles, or spines ("setose-spinulose," "appressed and dense spines")."
http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200023702

"Adaxial" leaf surfaces = upper leaf surfaces

I dunno... as I said in the disclaimer  , I don't know much about thistles... but, based on the above (which corroborates the F. of A. key),  I think your thistle is pointing to C. vulgare... ?

Here's a closeup of the lower leaves of C. hookerianum, for comparison... said not to be scabrous, lacking appressed spines, in F. of A..   I think this photo shows a clear difference, which may be what the F. of A. key was trying to get across.  The leaves near the inflorescence on C. hookerianum become woolly, with tangled hairs, but not spiny (second photo).

Oh, and the other 2 native thistles are C. foliosum and C. scariosum.

tks, lori--i had already read the section of eflora you quote, and obviously saw my own pics but i had not been able to decide, based on available information, whether the 'hairs' in my photo were the sort of spines they are talking about; they are also not appressed, though i think there was a qualifier in the full text which said 'more or less' so if not at all falls withing more or less...lol
--i need to go out and see if there are some leaves on plants that did not flower and feel to see if those hairs are in fact bristly/spiny(i remember overall the plant did not feel very spiny, but i imagine this is a matter of degree relative to other species..)..if so, then vulgare it may well be.....
 there would remain, however, the issue of the white ridges on the phyllaries, and outward spine tips on phyllaries which do not match vulgare according to the same eflora; they also mention numbers of series of phyllaries, which seem low on my plant--though it would seem that could be affected by growing conditions--i.e.--a cold year, shady conditions might lead to smaller flower heads which could have fewer ranks of phyllaries? of course then we are into wild speculation on my part....lol

there are also characters based on the seeds, which i am working on absorbing as well, since i have a great pile of those safely bagged... in case its vulgare, i didn't want them floating about-though its clearly no important weed in my area (amazing enough, given the number of seeds from one plant!)..

i clearly spent too much time reading about thistles yesterday--i had species names floating around in my dreams last night its been a good exercise, brushing up on some botanical terms and getting myself wrapped around some of those used especially in Asteraceae..

[cohan]

well, i just managed to remember, while i was collecting branches for kindling, to look for immature rosettes, and managed to find one among the fallen  leaves..
on the broader immature leaves, the hairs/bristles/spines were easier to look at, even with the naked eye (i'll still try to get a photo for a macro view)--and while  very small and not prickly, they were much more appressed than on the cauline leaf in the prev photo, and could certainly be said to give a scabrous feel to the leaf, lacking still any other leaves to rub for comparison  
-so that does look like C vulgare, which still leaves me wondering about the out of place phyllary/involucre characters   maybe i have misread/understood the glutinous ridge on the phyllaries- which i took to be the whitish ridge down the centre...