Annual Bluegrass (Poa annua). A. Spikelet. B. Grain. This grass is never more than a foot tall. Its soft green leaves have the closed boat-shaped tips of other Poas (bluegrasses). Leaf sheaths enclose the stems for about 1/3 their length, and ligules are about a tenth of an inch long. The inflorescence is a panicle 1-3 inches long with 2-6 florets on short spikelets. Drawing: Lucretia Breazeale Hamilton. Reproduced with permission of the University of Arizona Press (Parker 1972).