Foundational Friend (I'll call her that because it was through her that I met much of my English social circle--including Better Half) stayed over last night and had the misfortune of seeing me this morning. Never a pretty sight--but particularly nasty today as I was horribly sneezy and snotty. I nodded toward a bouquet on the dresser and said, "I'm allergic to mums." FF followed my nod and it clicked. "Oh," she said, "you mean chrysanthemums." Yes, I did, and that must've been the fifth time I've had that exact exchange with an Englishperson. Will I never learn?
(I may learn to say chrysanthemum in full, but I won't learn to bin them when they're given to me. I believe in suffering a little for beauty and kindness.)
Mum for chrysanthemum is another case of American word-clipping that isn't shared by most speakers of British English. Americans also say chrysanthemum, but if you were raised in the funeral business as I was, it's handy to have a quicker way to say the names of common funeral flowers--so I say mums and glads (= gladioli). I notice that most of the examples of glads in the OED (1989) come from outside Britain--Ireland and Australia.
I think UK florists are missing a great opportunity in not clipping their chrysanthemums. Imagine the ads running up to Mothering Sunday: Mums for Mum! (= AmE Mom). Yes, that's Mothering Sunday. While these days it's often called Mother's Day, many Brits consider that to be a crass American name for the day. It's also a different day. Mothering Sunday is the fourth Sunday during Lent, which means it's generally in March. American Mother's Day is the second Sunday in May. (The first Mother's Day was on the anniversary of the death of Ana Jarvis' mother, which happened to fall on a Sunday that year. Who is Ana Jarvis? She's the inventor of Mother's Day.)
What this all means is that if you're an American expat in a Mothering Sunday country, you buy a card for your mother in March, with the intention of sending it in May. But then since no one's advertising Mother's Day in May, you forget all about it until you find the card in July. Or until your mother phones with stories of all the lovely things your brothers did for her on Mother's Day. Still, it must be worse to be a British expat trying to remember Mothering Sunday ten months after anyone's mentioned Mother's Day.