I bought a snowdrop at Anglesey Abbey that says it is an (unnamed) October-flowering form of Galanthus elwesii. it is certainly an elwesii and it has finished flowering; time will tell if it does flower reliably in October.
Now "Peter Gatehouse" will sometimes flower right at the end of October, but usually I have to wait until November. Also, "Remember Remember" manages to flower early in November. Is there a named elwesii cultivar that flowers reliably in October? And have autumn-flowering elwesii ever been observed in the wild or is this phenomenon only known in cultivated stock?