Did anyone ever noticed that although Bill Seidl stated that Sable is a diploid dark red single Lacti it was originally registered as a F2 from Albiflora x Otto Fröbel.
I guess Sable could be a tet and interesting for breeding and it explains the fertility of Valkyrie and its (supposed) sister seedling Old Soldier. BTW pictures show that Sable (still available in Russia) has a rather poor habitus hence many offspring (Corals etc.) where Otto Fröbel is involved