My seed for Arenaria tetraquetra from the 2013/2014 seedex gave me plants with woolly oval leaves. Quite interesting, but not at all like photos of the species that I've found online. It recently started blooming, with flowers much like those of A. grandiflora, so I think the genus might be correct. But which species?
My page about it is here: http://www.robsplants.com/plants/ArenaTetra
A few representative photos: