hoary alyssum(n = noun.plant) berteroa incana, hoary alison - tall European annual with downy grey-green foliage and dense heads of small white flowers followed by hairy pods; naturalized in North America; sometimes a troublesome weed;
is a kind of herb, herbaceous plant
is a member of berteroa, genus berteroa

alyssum, genus alyssum, hoary, hoary alison, hoary golden bush, hoary marmot, hoary pea, hoary plantain, hoary puccoon, hoary willow, sweet alyssum