WordNet sense 1 (Eurasian plant with heart-shaped trifoliate leaves and white purple-veined flowers):

common wood sorrel, cuckoo bread, Oxalis acetosella

WordNet sense 2 (creeping European clover having white to pink flowers and bright green leaves; naturalized in United States; widely grown for forage):

white clover, dutch clover, Trifolium repens

WordNet sense 3 (clover native to Ireland with yellowish flowers; often considered the true or original shamrock):

hop clover, lesser yellow trefoil, Trifolium dubium