Shamrock

Shamrock (Irish, seamrog), the national emblem of Ireland, a leaf with three leaflets, or plant having such leaves, sometimes supposed to be the Wood-sorrel (see OXALIDÆ), which unlike some of the rival claimants for the honour is certainly indigenous to Ireland. But the name is more frequently given to some species of Clover, or to some common plant of some of the nearly allied genera, as the Bird's-foot Trefoil (see BIRD'S-FOOT), or the Black Medick. It is not improbable that the name has a sort of general reference to plants with trifoliolate leaves indigenous to Ireland; a perfectly satisfactory determination of the species is apparently as impossible as the attainment of botanical accuracy in regard to the emblematic thistle of Scotland. Lesser Yellow Trefoil (Trifolium minus) is the plant usually sold in Dublin on St Patrick's Day. The Common White Clover in clover, though very rare in wood-sorrel)—still causes many a futile search. The shamrock is said to have been first assumed as the badge of Ireland from the circumstance that St Patrick made use of it to illustrate the doctrine of the Trinity. But the story is a late one, and is not found in any of the earlier lives of St Patrick; and so far as the theological argument is concerned, any plant with trifoliolate leaves would answer the saint's purpose equally well.