Aira L.
Spikelets 2–3 mm long, with 2 florets. Pedicels and branches thread-like and delicate Aira
Panicle open. Pedicels as long as or longer than the spikelets
Pedicels up to twice as long as spikelets
Spikelets mostly 2 mm long but up to 2.5 mm, mostly with 1 exserted awn but sometimes 2; glumes obtuse. Erect annual up to 25 cm high. Widespread. Chiefly grasslands. Introd. from the Mediterranean. Fl. spring. Silvery Hair Grass Aira cupaniana
Spikelets 2.5–3 mm long, mostly with 2 exserted awns but sometimes only 1. Glumes acute. Erect annual up to 30 cm high. Widespread. Grasslands; roadsides. Introd. from Europe. Fl. summer. Silvery Hair Grass Aira caryophyllea