Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
A couple of ideas:
Alder Cones (Alnus species)
Cones from Sequoia or Sequoiadendron
Both of these species make cones that look like that: flat plate-like scales with no thorns.
I suspect Alder, but I am not sure. Google some images, see what you think.