The New Jersey Native Plant Society has instructions for collecting, drying and storing of wildflower seed, with special mention of Polygala paucifolia. Web-site below.
Polygala paucifolia also spreads by rhizomes, to form colonies. New plants are formed at the end of the rhizomes and can be removed for transplanting in a suitable location.
Rhizomes can remain dormant for years, before sending up a new flowering stem.
BOL!

Here is a link that might be useful: Seed Collecting

They are somewhat difficult to transplant so seed would be the method of choice. Polygala was indigenous to our property and aone year a large section of the woods was covered with this delicate and attractive plant. Over the years it has virtually disappeared and this spring I could find only one little group.

A friend of mine sent me some of this from the adirondacks earlier this spring, it mailed (to ks) and transplanted fine, so I assume that as long as its kept moist it will be just fine. Mine never wilted in the box nor after I planted it. I think moisture is the key.

Paula