penny-grass

noun1

1. •
   (no longer used) yellow rattle (Rhinanthus minor or Rhinanthus major (syn. Rhinanthus crista-galli)).

   • Another Grass is called Penny-Grass; it groweth low, close to the Earth, in moorish Grounds; it hath a Leaf as broad as Twopence , but never beareth a Flower. — 1670