If anyone would like some fresh Magnolia wilsonii seed, please send me a PM.
It should be hardy throughout the UK (Cluny Gardens has one).
It loses viability quickly if dried, so not really suitable for the seed exchange.
Will need to be soaked in soapy water for a few days to get the flesh off.. ..then cold stratification for 3 months in the fridge.. ..then germinate at about 60 deg F.
Grows rapidly... my plant about 4m x 4m after 5yrs.. flowering after about the 3rd yr if you're lucky.