There it goes an image to illustrate Ian Barclay's description of "West Coast Silver Dollar", commonly grown in California :-) I grow it here in Northern Spain as an example of dieback perennial garden Eucalyptus and it behaves as stated above in my zone 8b yard.

"East Coast Silver Dollar" is also used as vernacular name for other types of eucalypts in the nursery trade in other areas of the USA, most commonly E. cinerea. Again, roundish silvery juvenile leaves, but not pendulous from short petioles as E. polyanthemos.

None of them are E. gunnii even if this one also can have round silvery leaves. And both are less cold hardy than the Cider Gum. E. gunnii "Silverdrop" is a small mystery itself :-)

Gus