Help ID a yellow flower w/8 distinctive petals

Found in eugene, oregon. Aprox 1 ft tall. Blooming in April, May, and June, perhaps more. I was only able to go to this location during those times. I thought the distinctive petals would help me ID it but so far have had no luck.

 

Coreopsis sp.
Do you have any pics with leaves?

 

unfortunately no, I was just taking photos for fun and not id purposes and then only wondered what it was later. I will be going back to the location next week so if I can find it I will take more pics of leaves and such.

 

try C. lanceolata

 

Coreopsis auriculata 'Nana'?
http://apalacheehills.com/SpeciesAdded05/coreopsisNana-1.jpg

 

ok new pics of leaves and such

 

My guess : coreopsis

I like the bee pollination thing going on in your photo !

 

I think 'saltcedar' nailed it with "Coreopsis auriculata 'Nana' "

 

thanks everyone :)
You guys where a huge help.