Only NARGS Members are entitled to order seed from the NARGS seed exchange.
There are benefits to both. Garden seed often results in more "Garden worthy" rock garden plants while wild collected seed may be more likely to yield plants which are true to name but not selected for floriferusness, etc..
Orders are filled and mailed out starting in January. The orders of Members who donate seed are filled before non-donors.
Become a seed donor!
Order seed early!
The original document is available at http://nargs.org/nargswiki/tiki-index.php?page=NARGS+seedEx+FAQs