Help with Identifying wood - Selig Z Chair  

Hi
I recently purchased this Selig Z Chair & Sofa and after a little research understand there are a few variations of wood used for construction. As far as I can tell this set has 2 different wood types. The chair arms are a much darker wood than the seat.
The sofa has the same type wood across the top, under the seat and the sides.
And if anyone can provide a link to the designer or any other information as to manufacturing date or (?) I will be grateful.
Thanks.
ps: I'm new to the forum and when I get the image posting format figured out I'll post images to the forum, but until then I've uploaded a couple images to my dropbox - hopefully this will load the images when you select the link.
http://www.dropbox.com/sh/dp4je3ucebzzry5/8yonivlpPI