Michael Joseph,
maybe I get hung up on symantics too much, but on the excellent link you supply to the Federal Reserve site, where they do seem to obfuscate their products bona fides, there is a link at the page bottom that then discussed coins.

http://www.federalreserve.gov/faqs/currency_12626.htm

They work to inform that:
The Board of Governors of the Federal Reserve System is the issuing authority for Federal Reserve notes, the primary form of currency in circulation in the United States.

For me the symantics comes from their use of primary, which would in my mind surely imply not the only form of currency...