Yes. Most likely Helianthus tuberosus, akaJerusalem artichoke. An aggressively spreading perennial sunflower, it produces edible tubers.

There are many species of sunflowers and not all of them produce those big seedheads and fat, tasty seeds

Well, after they all died and dried up (they were six to eight feet tall, with inch-diameter trunks), I dug them out, and I never saw anything like tubers in at least the few inches of soil I turned up. The seeds in these guys are millimeter-sized. So I guess some varieties of sunflowers produce small seed pods with seeds that size?

So I guess some varieties of sunflowers produce small seed pods with seeds that size?

There are many species of sunflowers and not all of them produce those big seedheads and fat, tasty seeds.

OK, I'm going to run with Helianthus annuus,which I now understand to be pretty natively endemic around here.

"spread somewhat invasively year after year" is what made me guess Helianthus tuberosus. It is a serious spreader/invasive and being perennial, returns year after year.

Both H. tuberosus and H. annuus share a very similar appearance so easily visually mistaken for each other.

I think it's Helianthus anuus. The leaves seem loi large for H. tuberosum. It's annual so it only apprears to be agressive because without deadheading they will be all over the place. The First Peoples to enter the continent selectively bred this annual species of sunflower to produce larger seeds over a period of hundreds or thousands of years. Technically speaking I would say any species in the genus Helianthus is a sunflower. Many other genera in the sunflower family Asteraceae which have yellow ray petals and disk flowers are also called some type of sunflower in their common names. The name Helianthus comes from helios meaning sun, and anthos meaning flower. Sun+flower. You can check the involucre to verify.

Heianthus tuberosa , Jerusalem Artichoke

Helianthus anuus, Annual Sunflower.