White and red clover (Trifolium repens and Trifolium pratense) are members of the plant family fabaceae, also known as the legume, bean or pea family. Their leaves are typically compound, i.e. they consist of several leaflets. There is speculation that the – in evolutionary terms – older members of the fabaceae have more leaflets and the younger ones like Trifolium less. That would mean that four-leaf clovers are reminiscent of their long-gone ancestors. One might even speculate that future clovers will typically have only two leaflets with some very rare, lucky exceptions with three leaflets. Note to website administrator in 100’000 years: please update!