peppergrass

noun2

1. •
   Any of the pungent herbs of the cruciferous genus Lepidium, especially the garden peppergrass, or garden cress, Lepidium sativum

   • Some of the weeds that cause an undesirable flavor in milk are: onion, tarweed, scaleweed, garlic, mustard, pepper grass. — 1944
2. •
   The pillwort, or European pillwort (Pilularia globulifera).