Indiana - zone 5

I've wanted to ID this one for several years now, but there are so many sunflower type plants.......

Perhaps something from oenothera?

It's about 5" tall and blooms for only a few weeks in September in the area of the lakeside where the water line has receded from the summer's drought. (moist and fertile)

I don't notice the plants until late in the summer, so perhaps they germinate late?

It doesn't transplant well, and I've tried collecting and starting seed for it to no avail. It just doesn't seem to like any form of cultivation......

Bidens aristosa
Western tickseed sunflower?

It's this one! http://wisplants.uwsp.edu/scri...

You have no idea how many hours I've spent in past years trying to get a definitive ID for this plant! Thank you!

You're an !

It's a Bidens, but it's not Bidens aristosa as that species has pinnate leaves. Might be Bidens laevis: http://plants.usda.gov/java/pr...

Kent,

Thank you!

I went out and looked at those again to see if the bloom stalks came out of the leaf axils; they do. I believe that Bidens laevis is this plant.