Unfortunately over time a number of misidentified seeds have been donated and distributed through the various rock garden seed exchanges including the NARGS Seed Exchange. Sometimes more vigorous plants which might be considered "thugs" or might be nice rock garden plants in their own right are donated. Sometimes a mistake was made in identification a long time ago and the correction hasn't caught up to all of the labels in everyone's garden. Perhaps the most common reason for misidentifying seed is that the bees and other pollinators were busy and didn't worry about a little cross pollination here and there!
One way to help avoid misidentified seed is to look up who donated it this year to see if you know them or ask other members if they know them or have visited their gardens and order seed donated by people who are known to be knowledgeable.
If you have seed of a nice rock garden plant whose name you are unsure of, you can donate it as a species? or hybrid? with a description as listed on the Seed Exchange donation form. For example:
Some plants which are commonly misidentified in the seed exchange and which people should be extremely careful to identify before donating seed are:
Created by Hannah.
The original document is available at http://nargs.org/nargswiki/tiki-index.php?page=Common+seed+masqueraders