Every day on the BBC homepage there is a 'fact of the day' from the comedy programme QI. Yesterday the fact began "Dandelions are also known as pissy beds, jack-piss-the-bed, wet-the-bed, wet-a-bed, tiddlebeds and pissenlit ..." I'm afraid I can't complete the rest of it, as it's a different fact today and that one has disappeared. However, I did check the info when I read it yesterday.
The Oxford English Dictionary has even more synonyms - pish-the-bed, pee-the-bed, pissy-pee and pissabed are four. All of these names derive from the fact that dandelion was once well known as a diuretic - and you didn't need to eat it to get the effect; a citation in the OED says that it was believed that just picking a dandelion could cause you to wet the bed.
The standard name of the flower, dandelion, derives from the French dent de lion or 'lion's tooth', so-called because of the shape of the leaves.