Plant Sharing

I think a valuable function of this site could be to integrate a plant sharing mechanism for those interested.  I particularly want access to a few species that I have had trouble coming by.  I also have a trove of plants to share.  Needs: water celery (non-flamingo type) straight up green, chinese artichoke, ostrich fern, apios.  Offering: Spineless Nopale (two burbank varieties obtained from Burbank homestead, mildly frost hardy, needs greenhouse), chinese water chestnut (same as previous), red flowered dwarf comfrey, two varieties of walking onion, potato onion, others.  I'm also looking for a larger bulbed potato onion, mine never reach size advertised (1 inch max.)  If anyone wants to sell species or offer in trade or can suggest good sources for the above needs, that would be awesome.