Can anyone identify this?

[Zeedman]

It's definitely a Senna. WHICH Senna, I'm less certain of. There are too many leaflets for S. acutifolia (the medically used Senna, and the one I'm most familiar with). Ditto S. occidentalis and S. tora. Herbacea, IS a possibility (and as the only Senna native to the US as far as I know, the one I'd go to if you said this was growing wildly.)

We planted one like that in our front yard when we lived in Florida and the nursery worker called it popcorn cassia plant.

If you rub the leaves they smell like popcorn. Ours grew huge! We kept pruning it.

Thank you to everyone for your responses. Senna didymobotrya, a.k.a. Popcorn Cassia, may be the one - it matches the plant habit, and that unique flower/bud structure. If so, it would explain why both of the plants I've seen were short - it is not hardy this far North. Maybe a related, hardier Senna? Or started from seed indoors?

To judge by some of the photos I've seen, I would probably be happy with any Senna hardy enough to tolerate my climate... which could prove to be a challenge, since the genus appears to be mostly tropical.

 

[Dirtmechanic]

I posted it on another site and got this answer from someone I respect when it comes to formal identification:

"This evergreen shrub is Popcorn Senna or Candelabra Tree (Senna didymobotrya) in the Pea Family (Fabaceae). It is native to tropical Africa. Though frost-tender, it grows fast enough to be used as an annual in cooler climates."