Many times my students have asked me the specific name for a mushroom and I have had no idea. Apart from champignons or shitake mushrooms, us English people usually have no clue! If it looks like a mushroom in England, we don’t call it anything special, just mushroom!
In England, it is not common to pick mushrooms. We do not get up at 5am on a Saturday and head to the forest with a basket. We simply go to Tesco. We do, however, sometimes pick fruit – strawberries, raspberries, blueberries etc. The important thing – and the reason for talking about mushrooms and fruit at all – is that we ‘pick’ them, not pick them ‘up’.
To’ pick’ means to pull it from its source, to ‘pick up’ means to get something which is loose on the floor, or collect a person or item from somewhere, e.g. I need to pick up my son from kindergarten.