Fig. 66. AiracaryophylleaL. SILVERY HAIR-GRASS.—a, = spikelet; 5, a 
two, awned florets. A second species of Aira is illustrated by fig. 153 in Bul. 
"66. AIRA Linn. Oi ah Pi. 63. 1758. Spikelets small, Wiowered; flowers her- 
; the 
first two persistent below the articulation of the rachilla, near ly equal, acut 2, 
: oe longer than the flowering glumes; Powering glumes closely epproak 
prene .and twisted be alittle st fi 
= Suerved: ae ae within the hardened sling ‘glume : 
d pal usually a tothem. Delicate annua ual grasses, with nar- 
row leaves 
— in pose North Africa, two introduced into the United 
