When you told me about the frothy green lace, I didn't realize that you were referring to seaweed. *boggles* Having seen many types of seaweed, i can't think of any that are both green and lacy, nevermind frothy. Seaweed is brownish reddish green, in a lot of cases (or black, or white in the only lacy case i can come up with).

< /rant >

Oh, reasoning for bemused confusion. Bemused is kinda a "smile and nod" confusion, in my head. According to online definitions, it can be to confuse or daze, or (in one def.) to confuse emotionally.