Family 1. POACEAE 
By GEORGE VALENTINE NasH 
Annual or perennial, sometimes monoecious or dioecious, herbs, or rarely 
shrubs or trees. Stems (culms) generally hollow, occasionally solid, the nodes 
closed. Leaves sheathing the stem, the sheaths usually split to the base on the 
side opposite to the blade, rarely closed ; a scarious or cartilaginous, sometimes 
herbaceous, naked or hairy ring, called the ligule, is borne at the orifice of the 
sheath, rarely wanting. Inflorescence spicate, racemose, or paniculate, con- 
sisting of spikelets composed of 2-many 2-ranked, very rarely spiral, imbricate 
bracts, called scales (glumes), the lower 1-4, usually 2, empty, or these rarely 
wanting. The remaining scales, excepting sometimes the terminal ones, con- 
tain in the axil a flower which is usually enclosed in a bract-like awnless organ 
called the palet, placed opposite to the scale and with its back toward the axis 
(rachilla) of the spikelet, generally 2-, rarely 1-nerved ; palet sometimes present 
without the flower, and vice versa. Flowers perfect, pistillate, or staminate, 
subtended by 1-3 hyaline, usually minute, scales, called lodicules. Stamens 
1-6, usually 3, rarely numerous. Anthers versatile, 2-celled. Ovary 1-celled, 
l-ovuled. Styles 1-3, commonly 2 and lateral, rarely 1. Stigmas hairy or 
plumose. Fruit a seed-like grain, the caryopsis, or sometimes a nut or berry 
in some of the Bambuseae. Endosperm starchy. 
A. Spikelets articulated below the empty scales (also in a few genera in B), or below a subtending 
involucre, deciduous alone, in groups, or with the surrounding involucre, or persistent and 
falling with the internodes of a readily disarticulating rachis; 1- or 2-flowered, if 2-flowered 
the first or lower flower staminate, very rarely perfect, the upper flower perfect ; rachilla not 
extending beyond the scales and its internodes not measurable. 
Spikelets arranged in spikes, racemes, or spike-like racemes, these sometimes forming panicles, 
the axis articulate, rarely continuous; empty scales firmer than the rest, the first scale 
the largest and enclosing the others, the fruiting scales and palets hyaline, "delicate. 
Spikelets unisexual, arranged in different parts of the same or 
in different inflorescences. Tribe 1. MaypEasr. 
Spikelets in pairs (rarely single or in 3’s), one sessile, the other 
pedicellate (rarely both pedicellate), all perfect, or the pedi- 
cellate staminate, empty, or sometimes wanting. Tribe 2, ANDROPOGONEAE. 
Spikelets paniculate, or if in racemes or spikes the axis continu- 
ous; empty scales not firmer than the rest, the first scale 
smaller than the others, the fruiting scales and palets rarely 
hyaline. 
Spikelets round or dorsally compressed (laterally compressed 
in Arthropogon and Lithachne); hilum punctiform. 
Fruiting scales and palets membranous, resembling the other 
scales in texture. 
Spikelets arranged in a single spike or raceme, deciduous 
singly or in groups. Tribe 3. ZOVSIEAE. 
Spikelets arranged in panicled racemes. Tribe 4. TRISTEGINEAE. 
Fruiting scales and palets chartaceous, coriaceous, or carti- 
laginous, differing in color, texture, and appearanice from, 
and usually firmer than, the other scales. Tribe 5. PANICEAE. 
Spikelets laterally compressed ; hilum linear. Tribe 6. ORYZEAE. 
B. Spikelets not articulated below the empty scales (rarely so in a 
few genera of the Agrostideae, Aveneae, and Chlorideae), but 
above them or between the flowering scales, hence the empty 
scales persistent after the fall of the remainder of the spikelet ; 
i-many-flowered, the lower flower perfect, very rarely staminate, 
the upper ones imperfect or wanting; rachilla often extending 
beyond the scales, its internodes usually measurable. 
Stems herbaceous, ‘annual ; leaf-blades usually sessile and not 
articulated with the sheath, rarely petiolate and articulated. 
VoLUME 17, Part 1, 1909] 
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