I don't have (much) of an opinion about which species it is. But, I do know this, Conyza canadensis is a highly variable species. It's leaves can be very rough and hairy (which is what coarsely hirsute means) or very smooth (glabrous). I've seen flowering individual plants anywhere from 6 inches to 10 - 15 feet tall. Leaf size is similarly variable. In short, the plant pictured in the original post absolutely CAN be Conyza canadensis, although you might have to wait for flowers to be sure which species it is. That said, I wouldn't recommend allowing it to flower since both species are a pain in the rear in garden situations.
