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Poaceae (R. Brown) Barnhart
Grass Family
禾本科
Authors: Chang-Sheng Kuoh
Gramineae Adans.
Annual or perennial herbs, rather rarely with woody perennial culms (subfamily Bambusoideae); hollow or solid, septate at the nodes. Leaves two-ranked, consisting of the sheaths, ligules and the blades. Leaf-blades mostly linear and not petiolate at base, rarely with broad blades and stipitate at base (subfamily Bambusoideae); ligules membranous or ciliate, rarely lacking (Echinochloa), leaf-sheaths clothed at the internodes. Flowers bisexual or occasionally unisexual, without distinct perianth, it representing by 2 or 3 small scales, the lodicules, rarely six or sometimes absent; stamen mostly 3, rarely variable numbers, with filiform filaments and 2-celled anthers; pistil 1, ovary 1-loculed, containg 1 anatropous ovule, the style with plumose stigmas. Fruit mostly a caryopsis with rich endosperm, the embryo at the base opposite to punctiform or linear hilum which facing the palea. Flowers sessile between abaxial lemma and adaxial palea, constituting a floret. One to many florets dispoded alternatly on the oppostie sides of rachilla, in addition with a pair of empty glumes at the base forming a spikelet. Inflorescence with spikelets as an unit aggregate into panicle, raceme or spikes.
Hsu(1974) treated 5 subfamilies (excluding Bambusoideae), 27 tribes, 118 genera, 289 species, 1 subspecies, 39 varieties, and 8 forms in Taiwan.
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KEY TO THE SUBFAMILIES
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| 1 |
Culms woody, perennial; blade-base articulating from the sheath, ussually petiolate |
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subfam. 6. Bambusoideae |
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Culms herbaceous, annual or perennial and not woody; blade-base not articulating from the sheath. |
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(2) |
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| 2 (1) |
Spikelets of one to many florets, if bearing two florets then the lower floret usually
perfect; spikelets terete or laterally compressed, breaking up at maturity above the more or less persistent glumes |
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(3) |
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Spikelets of two florets (1 floret in Sphaerocaryum), the lower staminate or neutral,
the upper mostly perfect, fertile; spikelets usually dorsally compressed, falling of entirely together with glumes at maturity; length of embryo more than 1/3 as long as the spikelet |
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subfam. 5. Panicoideae |
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| 3 (2) |
Glumes usually wanting or inconspicuous; palea odd-nerved, if 2-nerved, then
linear or enclosed in a sac-like lemma |
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subfam. 1. Oryzoideae |
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Glumes distinct; paleas 2-keeled or inconspicuous nerved |
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(4) |
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| 4 (3) |
Lemmas 5- to many-nerved; blade-base devoid of long hairs; length of embryo
less than 1/4 as long as the caryopsis; lodicules acute or acuminate, nerveless |
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subfam. 3. Festucoideae |
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Lemmas 1- to 3-nerved, or nearly nerveless; blade-base ususally with long
hairs, length of embryo more than 1/3 as long as the caryopsis; lodicules truncate, nerved. |
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(5) |
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| 5 (4) |
Lemmas distinctly nerved; spikelets nearly terete, laterally compressed; usually a tall reed |
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subfam. 2. Arundinoideae |
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Lemmas faintly nerved; spikelets compressed; small to medium sized grasses |
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subfam. 4. Eragrostioideae |
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List of Keys
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List of lower taxa
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Treatments in Other Floras @ www.efloras.org
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