What Are Those Things Of Colours??

I know that cover is ususal,But I have never seen on other covers those things.What are them???

They seem to be stickers depicting poinsettias for Christmas.
Regards, Robert

Poinsettias are an icon of Christmas.

They don't look right to me though,
they don't appear in concert for 1912.
I wonder what other members think?
Placed on the cover years after? self stick?

Worldwide Poinsettias on Christmas stamps
A self stick sticker poinsettia from a 1960 circa "on piece"
(top LHS)

Typical turn-of-the-century stickers. They came in a little box the size of a matchbox, 100 stickers with thick yellow gum (no self-stick then). They show up over and over on old covers and in old collections.

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The 6c orange Washington is quite scarce on cover, even in that condition, and especially in conjunction with a Registration stamp! That strikes me as (at least) a $10 item, to the right specialist.

Thanks for that Doug.
Appreciating the cover myself, (Lovely Registration aux marking)

I agree with doug. Nice example of double-rate with F1 stamp.