poaceæ

from The Century Dictionary.

• noun A series or division of the order Gramineæ, the grasses, distinguished from the other similar division, Paniceæ by the absence of a joint to the pedicel beneath the glumes, and by the presence of a stalk or empty glumes or imperfect flowers above the fertile flowers. It includes the larger part of the glasses, or about 200 genera (Poa being the type), in 7 tribes and 21 subtribes.