I know what they looked like before transplant. I transplanted from several places with volunteers to one area where I'm trying to grow them. Then I failed to eliminate the volunteers in each of those source locations. I'm pretty sure the source locations had all expanded by runner rather than seed (so transplants are clones of the ones left behind, rather than just related).
So I have several reasons to be sure it is the same plant.
Maybe the difference is sunlight. All the volunteers are in spots with full sun in parts of the morning, patchy shade (through the tops of distant trees) midday and full shade afternoon. The transplants have full shade in the morning, full sun midday and patchy shade later. The total amount of sun is similar. But other plant descriptions imply they are picky about whether sun is morning vs. other times. But more likely it is a soil difference (the soil everywhere in my yard is acid, but there are likely other differences between locations).