White mushrooms, baby bella mushrooms (aka cremini), and portobellos are some of the most popular types of mushrooms found in North American grocery stores.
The reason why these mushrooms appear different is because they were harvested at different ages in their growth cycle and they were selectively bred for color.
Are fully mature brown strains of Agaricus bisporus and have had time for a much deeper flavor to concentrate.They have a drier, meaty texture that's great for grilling.