Portobello mushroom on whatamieating.com

Description: Portabella or chestnut mushroom. The portabella or chestnut mushroom is a form of the cultivated mushroom and look similar to the common white cap mushroom available in most supermarkets but with a beige to brown cap. They have a little more flavour and keep their shape well during cooking. Cultivated mushrooms are the mushrooms commonly found on sale and come in many forms. Button mushrooms are a ball-shaped, immature form of cultivated mushroom, harvested before the gills are exposed and which mature to an open cap style and then to flat mushrooms. There are brown and white forms, the brown being called brown mushrooms or chestnut mushrooms and, more recently, crimini mushrooms. A clever marketing strategy has been to give them Italian sounding names, including portobellini for small brown button mushrooms through to portobello or portabella for the larger brown mushrooms. Nonetheless, despite the numerous names, they are all forms of the basic cultivated mushroom. (If gathering mushrooms you must be absolutely certain what you have before you eat them as many are very poisonous.)