536 THE GRASS FAMILY. [Poa. 
top without any prominent keel. Grain usually but not always free from 
the palea. 
Beiarae genus, widely spread over most parts of the world. Although in 
many’respects a natural one, its characters and limits are far from precise. 
It differs from Festuca only in its shorter glumes, without awns or decided 
points, and some species have been placed alternately in the one or the 
other genus. The first seven species are frequently separated, and formed 
into one, two, or more genera, characterized by minute differences in the 
nerves of the glumes or in the shape of the minute floral scales, or of the 
seed; and on the other hand, Catabrosa, Molinia, Triodia, Dactylis, and 
Keleria, although universally admitted, are distinguished by characters of 
very little more value. In the present state of our acquaintance with the 
most practical principles of classification in Grasses, the limits of Poa, as 
here retained, appear to be the most natural. 
Tall, aquatic plants. Spikelets not much flattened. Flowering 
glumes rounded on the back, with prominent veins, but not 
distinctly keeled. 
Panicle large and spreading. Spikelets 3 to 5 lines long . Ll. P. aquatica. 
Panicle long and narrow. Spikelets erect, 6 lines to an inch 
long . ; : ; - : : 5 A ‘< : . 2 PL. fluitans. 
Plants not aquatic. 
Panicle one-sidedand stiff. Flowering glumes rounded on the 
back, at least at the base. 
Panicle rather loose, 4to 6 inches long. Glumes almost nerve- 
less. Stock perennial. 
Stem creeping at the base. Flowering glume about 14 
lines long. 
Leaf-sheaths much flattened . ‘ ° ° ° . 9. P. compressa. 
Leaf-sheaths not flattened . 3. P. maritima. 
Stems tutted. Flowering glumes about i line long . 4. P. distans, 
Panicle compact, seldom 3 inches long. Spikelets crowded. Root 
annual. 
Spikelets about 3- or 4-flowered. Flowering glumes 
strongly nerved 5. P. procumbens, 
Spikelets 6- or more flowered. Flowering elumes faintly 
nerved : 6. P. rigida. 
Panicle reduced to a single spike, with the lower spikelets occas 
sionally clustered. Root annual . 7. P. loliacea. 
Panicle scarcely one-sided, the branches and pedicels slender. 
Flowering glumes all keeled, with minute silky hairs on 
the keel or sides. 
Root annual. No hairs on the axis of the Spikelet : 8. P. annua. 
Stock perennial. Minute woolly hairs on the axis under the 
flowering glumes. 
Panicle ovate or oblong, more or less crowded. 
Stem creeping at the base. Leaf-stalks much flattened 9. P. compressa. 
pars tufted. Stems and lower sheaths thickened at the 
ase. : 
Stems bulbous at the base. Panicle contracted . . 15. P. bulbosa, 
Stems scarcely bulbous. Panicle rather loose < . 14. P. alpina. 
Panicle loose or very long. 
Glumes pointed. Flowers about 3. 
Panicle long. Spikelets oblong or lanceolate. 
Stems weak. Leaves narrow and flaccid. Panicle 
slender : . 12. P. nemoralis. 
Stems tall. Leaves lon g and stiff. Panicle very “long 
and rather stiff . : . Molinia cerulea. 
Panicle very spreading, with ‘slender branches, and 
few, rather large, ovate spikelets. (Alpine plant. ). 18. P. lawa. 
Flowering glumes rather obtuse. Panicle spreading, with 
numerous spikelets. 
Rootstock with creeping scions. Flowers about 4 in the 
