A new ‘wildflower’ to learn?

Stuff grows so fast in the spring! This "weed" or "wildflower" was in someone's yard, quite tall but as yet uncut. It doesn't look familiar to me at all and of course I haven't a guess: submitted to my botanist friend for ID'ing.

My plant systematics expert says “Packera glabella (Butterweed), possibly herbicided.”

Species page at PhytoImages, http://phytoimages.siu.edu/cgi-bin/dol/dol_terminal.pl?taxon_name=Packera_glabella&rank=binomial

1 year ago (“Then, what I've done, you must do.”): http://365project.org/rhoing/365/2015-04-01
2 years ago (“More coffee refractions”): http://365project.org/rhoing/365/2014-04-01
3 years ago (“Portulaca”): http://365project.org/rhoing/365/2013-04-01
4 years ago (“Nature’s ‘SuperBall’?”): http://365project.org/rhoing/365/2012-04-01
5 years ago (“Now, now, kids!”): http://365project.org/rhoing/365/2011-04-01

[ IMG_9540S8x12Atm :: f/10 :: 1/1000" :: ISO-800 :: 60mm ]

[Lisa Pouncy]

Do you think it might be oil seed rape? It's such a fast growing and invasive plant...and also really bad for me as someone with asthma! xx

[Thom Mitchell]

@psychographer I don't think it is; the structure of the stems or trunks don't seem to match. But then I have been wrong in these IDs much, much more often than I have been right!

[Thom Mitchell]

@psychographer My expert says Butterweed (Packera glabella), "possibly herbicided."