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Taiwan Gramineae | Family List

Poaceae (R. Brown) Barnhart

Grass Family


Authors: Chang-Sheng Kuoh

Poa annua
leaf cs section

Credit: cs 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.


    1 Culms woody, perennial; blade-base articulating from the sheath, ussually petiolate   subfam. 6. Bambusoideae
    + Culms herbaceous, annual or perennial and not woody; blade-base not articulating from the sheath.   (2)
    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   (3)
    + 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.{subfam.Panicoideae]   (25)
    3 (2) Glumes usually wanting or inconspicuous; palea odd-nerved, if 2-nerved, then linear or enclosed in a sac-like lemma.[Oryzoideae]   (6)
    + Glumes distinct; paleas 2-keeled or inconspicuous nerved   (4)
    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.[subfam. Festucoideae]   (8)
    + 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.   (5)
    5 (4) Lemmas distinctly nerved; spikelets nearly terete, laterally compressed; usually a tall reed[subfam. Arundinoideae]   (17)
    + Lemmas faintly nerved; spikelets compressed; small to medium sized grasses[subfam. Eragrostioideae]   (19)
    6 (3) Glumes absent or minute, wet-land, aquatic or swampy places.   (7)
    + Glumes well developed   Phareae
    7 (6) Spikelets unisexual.   Zizanieae
    + Spikelets bisexual   Oryzeae
    8 (4) Ovary with a hairy appendage at the apex; caryopsis adnate to the palea, hilum linear.   (9)
    + Ovary glabrous, if hairy, without hairy appendage at the apex; caryopsis not adnate to the palea   (11)
    9 (8) Spikelets pedicelled in a panicle   Bromeae
    + Spikelets sessile or nearly sessile on the rachis of a solitary spike or raceme.   (10)
    10 (9) Spikelets shortly pedicelled, on a raceme; awn terminal   Brachypodieae
    + Spikelets sessile on opposite sides of the rachis   Triticeae
    11 (8) Lemmas 7-11-nerved; lodicule one, fleshy, truncate   Meliceae
    + Lemmas mostly 5-nerved (7-11-nerved n Avena); lodicules 2, acute or acuminate.   (12)
    12 (11) Spikelets one to several-flowered; lemmas not coriaceous, nerves distinct; sheaath margins adnate at least at the basal part.   (13)
    + Spikelets one-flowered; lemmas coriaceous, nerves not distinct; sheath margins free.   (14)
    13 (12) Glumes distinct, much shorter than the lowest lemma; flowers usually more than two.   Festuceae
    + Glumes longer or nearly as long as the lowest lemma; florets 1, 3 or several.   Agrostideae
    14 (12) Caryopsis large, with a hard beak at the apex   Phaenospermeae
    + Caryopsis much smaller, without a beak.   (15)
    15 (14) Lemmas awnless; dorsally compressed.   Milieae
    + Lemmas awned, terete   (16)
    16 (15) Awns trifid.   Aristideae
    + Awn simple, sometimes flanked by 2 bristles.   Stipeae
    17 (5) Spikelets 2-flowered, the lower empty; spikelets falling off with part of the pedicel attached   Thysanolaeneae
    + Spikelets several-flowered   (18)
    18 (17) Blades broad and tessellately nerved, ususally with a petiole   Centotheceae
    + Blades linear or lanceolate, nerves not tessellate   Arundineae
    19 (5) Spikelets with several to many fertile florets   Eragrostea
    + Spikelets with only one fertile floret.   (20)
    20 (19) Glumes coriaceous and usually longer than the lemma.   (21)
    + Glumes thinner or of the same texture as the lemma, shorter than the lemma   (23)
    21 (20) Inflorescence in a contracted and simplified panicle or a terminal raceme.   (22)
    + Inflorescence a spike; spikelets sunken in the rachis joints   Leptureae
    22 (21) Upper and lower glumes equal in length, both awned; peduncle slender and weak   Perotideae
    + Upper glumes awnless, lower glume minute or wanting; peduncle stout   Zoysieae
    23 (20) Spikelets cylindrical, falling entire; base of the glumes bearded; lemmas awned   Garnotieae
    + Spikelets more or less compressed; base of the glumes not bearded.   (24)
    24 (23) Inflorescence in digitate racemes or a terminal spike   Chlorideae
    + Inflorescence in an open or contracted panicle   Sporoboleae
    25 (2) Spikelets articulating above the glumes, if articulating below the glumes, then 1-flowered and lemma membranous.   (26)
    + Spikelets articulating below the glumes; spikelets usually 2-flowered, paired or solitary.   (27)
    26 (25) Callus glabrous; spikelets one or 2-flowered, usually awnless   Isachneae
    + Callus hairy; spikelets 2-flowered, awned   Arundinelleae
    27 (25) Upper lemma and palea coriaceous; thicker than the glumes   Paniceae
    + Upper lemma and palea membranous; thinner than the glumes   Andropogoneae

    List of Keys

  • List of lower taxa


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