Poa and Festuca (see p. [116]) are difficult genera for the beginner; several of the species vary considerably in detail. Generally speaking the spikelets of Festuca are hard, harsh and sharply pointed, or with short or evident awns; in Poa they are softer, and with blunter points, and never awned. The most obviously awned species of Festuca have more or less setaceous leaves and contracted inflorescences (see p. [111]). Some of the mountain species of Poa are extremely variable in small characters.
≡ Reed-like aquatic, with obtuse glumes rounded dorsally; the large richly branched panicle bearing numerous 5-10 flowered spikelets. Sheath entire or nearly so. No web to the paleæ.
Glyceria aquatica, Sm.
For other reed-grasses, see note, p. [103]. Glyceria fluitans has a more contracted panicle and usually more flowers in the spikelet &c. (see p. [111]).
≡ ≡ Meadow and pasture grasses &c., usually small. Glumes more or less keeled and acute. Sheaths split.
Poa.
‡ Spikelets very small and containing 2-3 flowers only. Stem slender, terete and rough; ligule long and acute, palea with prominent lateral nerves.
P. trivialis, L.
The flowers are fewer than in any other Poa, and may be only two. P. nemoralis, with 3-5 flowers, may also occasionally be found with two only: it differs from others in its more acute glumes, smooth stem and short ligule.
P. pratensis differs in its creeping stolons, short ligule and more numerous 4-5 flowers, and in the indistinct nerves of the palea.