Game Time: ID this plant!

Species name: Asteraceae (Callistephus chinensis? Bellis perennis? Campuloclinium macrocephalum?)

Common name: A pretty purple pom pom aster

Location: Ontario

To be honest, I have no clue what this plant is. I've managed to narrow it down to the sunflower family or the Asteraceae, but that's all I've got. I found two species that might be close to the ID of this plant, but I'm doubtful that either are the correct species name. I've got my best three guesses below; if you have a better suggestion, please leave it in the comments below! Unfortunately, I have no way of going back to get photos of other features of this plant; it seems it was planted in the late fall as a "Welcome to Campus!" symbol (the school's colours are purple and white) for Autumn Convocation and have since been ripped out.

C. chinensis is otherwise known as the China aster, and is native to (you guessed it) China. It is a popular ornamental plant in North America, but the leaves seem to be quite different than the plant that I photographed. They have more obviously toothed or lobed leaves, and they aren't as hairy and thick as the leaves on the plant I found on campus. Other than the ornamental value of this plant, it has no other uses. It also, to my knowledge, is not invasive in North America (but it might be in other locations).

B. perennis is also known as the English daisy, and the wildtype of this plant (what we call a species that has not been cultivated and is growing freely on its own accord) is very different than the cultivated varieties. The natural version of this plant (native to Europe but naturalized through much of North America) looks very much like your typical daisy, with white ray florets and yellow disc florets. There are sponaneous mutations in the wild that cause either a change in ray floret colour, a change in disc floret colour, what is referred to as "petal doubling" or the conversion of (in the case of this species) disc florets into ray florets, or all three. There are quite a few cultivars that have pink to purple ray florets and disc florets, fringed ray florets, and petal doubling. Again, the leaves don't quite seem to fit the description of the species, so I doubt this is the correct identification of the plant. If it was, this plant would be used in homeopathic medicine as a wound healer due to its astringent properties (usually a tincture is made from the rhizomes; this makes me wonder if it's the plant's action or the action of the alcohol with which it is mixed that makes the treatment effective).

C. macrocephalum, also known as the pompom weed, is the last potential plant that I think is a close fit to the photos that I took and what I remember of the plant. This species is native to South America, but has been introduced to much of the rest of the world. In South Africa, it is one of the most destructive plants that has ever been introduced there; it is an incredibly vigorous competitor and threatens to completely decimate natural grasslands by outcompeting native species. The plant has the ability to turn grasslands completely pinkish-purple during the summer months (remember that summer there is from December to March!), much like our previous problem with purple loosestrife in North America. I haven't ever seen the leaves of this plant (there don't seem to be many photos of the whole plant on the internet; just the very conspicuous flowers), so I don't know if they would be a good fit.