Gramineae Poaceae - Grass, a monocotyledonous green plant used to describe it and related plants in the rush (Juncaceae) and sedge (Cyperaceae) families, that somewhat resemble grass.  Grass-like plants are among the most versatile life-forms.  The term came about in the early 15th century, from the Old English græs, derived from the same root as "grow".  A single piece of grass is called a blade of grass.  Grass plays a central role in two important science fiction catastrophe novels from the 1940s and 1950s:  Ward Moore's Greener Than You Think, in which the world is slowly taken over by unstoppable Bermuda Grass, and John Christopher's The Death of Grass, in which a plague that kills off all forms of grass threatens the survival of the human species.  The grass  is the favorite performing surface for Castle Wall members. The grass plays Prince John’s Tournament Field in the 2008 season.