Being new to fern identification, I'd like confirmation that the fern
in

http://www.flickr.com/photos/raphanus97/

is in fact Ptridium aquilinum. The fern seems to be tripinnate on the
lower part of the frond and bipinnate at the top. Have I got this
right?

The fern is a volunteer in my newly landscape backyard in Aiken County,
SC.

Thanks.