No. Four-leaf clovers are usually the same species as common three-leaf clovers; the fourth leaflet is a mutation or developmental variant.

Yes. Selective seed saving from plants that produce four leaves at higher rates can increase frequency in progeny, though genetic results vary.

No. Collecting clovers in public parks may have local rules; always respect private property and local regulations.

Shamrock usually means a three-leaf clover and is a cultural symbol of Ireland. Clover is the common plant name applied to species in the genus Trifolium.