WordNet (r) 3.0 (2006):

pin clover
    n 1: European weed naturalized in southwestern United States and
         Mexico having reddish decumbent stems with small fernlike
         leaves and small deep reddish-lavender flowers followed by
         slender fruits that stick straight up; often grown for
         forage [syn: redstem storksbill, alfilaria,
         alfileria, filaree, filaria, clocks, pin grass,
         pin clover, Erodium cicutarium]