Please Help me ID this Plant

I received this plant from a horticulture student at the University of Minnesota and I've spent the last 3 years trying to figure out what it is. This mystery plant is a perennial surviving cold Minnesota Winters. It produces several small yellow flowers (about 2" diameter). These yellow flowers produce several pedals (similar to a daisy)... See pictures of the leaves below.

 

Not sure what it is, but are the stems square ?

 

This plant has a square stem.

 

A similar plant here gets to about 2.5m {7-8'} tall.

 

Doronicum?

What time of year is it flowering? Doronicum is spring-flowering.

 

Silphium perfoliatum may be?

 

Thank you Trylych, that seems to match the plant here. The plant usually blooms in mid summer Michael. The leaves here are cupped at the stem, holding water.

 

Silphium perfoliatum and S. integrifolium varieties are native to Minnesota and apparently natural hybrids occur.