The height is suggestive of L. leucanthum. The variation in the colouration, particularly among the offspring, however, makes me suspect that this is an infraspecific form - neither centifolium nor chloraster (aka var. leucanthum) but a possibly hybrid of the two. This can be the problem with subdividing species into varieties... even in nature there almost always exists an intermediate form!
I'll do some more checks when I have time, but I'm leaning towards classifying it as an infraspecific L. leucanthum hybrid.
