Mushrooms come in different shapes and sizes and different varieties. Since different varieties share similarities in shape and size, it takes a trained eye to identify a particular mushroom with precision. While some common mushrooms are safe to eat, some others are extremely toxic and can be fatal to eat. Therefore the task of picking mushroom for consumption should be left to the experienced or those trained in the agrarian field. It is otherwise an impossible task for an ordinary person to tell what type of mushroom a particular piece is.
The methods of identification in use today include a combination of ancient plus modern methods. Long ago, a keen expert eye would observe the spore prints made on a surface by the powdery stuff emitted from the mushroom gills, where both colour and patterns were extremely significant. The colours to look for included mostly white, but there was also black, brown, yellow, purple-brown, and cream. Modern categorisation of mushroom involves scientific testing of samples in a laboratory.
Considering the possible repercussions of eating a poisonous piece of mushroom, it is wise to cook only mushrooms sourced from an expert