Trefoil, White clover
Mainly considered a weed when we find it in our lawns, clover is actually a valuable part of our food chain. Clover provides an important source of nectar for honeybees. It is commonly cultivated as fodder because it continues to produce a palatable crop even after repeated mowings or munchings. It also adds nitrogen to the soil so is often used as a cover crop.
And if whilst inspecting it, you find a four leaf clover it's your lucky day!