Probably not worth a new thread, as I could've asked this over in Bingley's brown bell, where mushrooms were mentioned. I'll take a chance on it thudding into the abyss, though, rather than further confuse the dung issue:

Which is correct - Portobello or Portabella? (consuelo? emanuela? anyone?) Citations, please. This has been bothering me for years (yes, I know I need to get a life, and I will next month )