GRASS FAMILY 
195 
shaped tips. Spikelets 2 to several-flowered, the uppermost floret re¬ 
duced or rudimentary. Glumes acute, keeled, somewhat unequal, the 
first 1-nerved, the second usually 3-nerved. Lemmas somewhat keeled, 
acute or acutish, awnless, membranous, often somewhat scarious at the 
tip, 5-nerved. (Greek poa, grass or fodder.) 
Annual; lemmas not cottony at base, 5-nerved, the nerves pilose on lower half. 
1. P. annua. 
Perennial. 
Plants sod-forming, with creeping rhizomes; lemmas copiously cottony at 
base.......2. P. pratensis. 
Plants in bunches, without creeping rhizomes; lemmas not cottony at base. 
3. P. scabrella. 
1. P. annua L. In tufts or mats; culms flattened, 0.8 to 2 dm. long, 
decumbent at base, sometimes rooting at the lower nodes; blades soft; 
panicle 2.5 to 7 cm. long; spikelets crowded, 3 to 6-flowered, 3 to 4 mm. 
long.—Open ground, along roadsides and in waste places; nat. from Eur. 
2. P. pratensis L. Kentucky Blue Grass. Culms tufted, 3 to 9 dm. 
high, terete or slightly flattened; sheaths smooth, compressed; ligule 
about 2 mm. long; blades soft, flat or folded, the basal often elongate; 
panicle pyramidal, open, the slender branches in remote fascicles of 3 to 
5, ascending or spreading, naked at base, some of them short ; spikelets 
crowded, 3 to 5-flowered, 4 to 5 mm. long; lemmas 3 mm. long, copiously 
cottony at base, silky villous on keel and marginal nerves, the inter¬ 
mediate nerves prominent.—Open woods or open ground; extensively cult, 
as a pasture and lawn grass. 
3. P. scabrella (Thurb.) Benth. Malpais Blue Grass. Densely 
tufted; culms erect, 6 to 9 dm. high, usually scabrous, at least below 
panicle; sheaths scabrous; ligule 3 to 5 mm. long; blades mostly basal, 
flat, narrow, usually about 1 mm. wide, lax, more or less scabrous; 
panicle narrow, usually contracted, sometimes rather open at base, 5 to 
12 cm. long; spikelets narrow, 6 to 10 mm. long; glumes scabrous; 
lemmas 4 mm. long, puberulent or scabrous on back, and more or less 
crisp-pubescent on lower half.—Meadows, woods, rocks and hills, 
common. 
4. BRIZA L. Quaking Grass 
Ours low annuals with erect culms, flat blades, and open showy pan¬ 
icles, the pedicels capillary, the spikelets vibrating in the wind. Spikelets 
several-flowered, broad, often cordate, the florets crowded and spreading 
horizontally, the uppermost floret reduced. Glumes about equal, broad, 
papery-chartaceous, with scarious margins. Lemmas papery, broad, with 
scarious spreading margins, cordate at base. Palea much shorter than 
the lemma. (Ancient Greek name for some grain, probably rye.) 
1. B. minor L. Culms 1 to 3.8 dm. high; panicle pyramidal; spike¬ 
lets triangular-ovate, 3 mm. long.—Waste places, cent. Cal.; nat. from 
Eur. 
5. ERAGROSTIS Host 
Spikelets few to many-flowered, the florets usually closely imbricate, 
the lemmas often deciduous, the paleas persistent. Glumes somewhat 
unequal, shorter than the first lemma, acute or acuminate, 1-nerved, or the 
second rarely 3-nerved. Lemmas acute or acuminate, keeled or rounded 
