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Poaceae

禾本科

Flora of Taiwan
Gramineae 禾本科
特徵描述
屬列表
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特徵描述

[ Gramineae 禾本科 ]

作者

HSU, Chien-Chang

型態特徵

Annuals or perennials herbs, rather rarely with woody perennials culms (subfamily Bambusoideae); hollow or solid, septate at nodes. Perennials herbs or their branches at base usually with scales (cataphylls, transformed leaf sheaths). Leaves two-ranked, consisting of a sheath, ligule, and a blade. Axillary buds when grown out into a branch provided with a usually 2-nerved bract (prophyll) between branch and culm. Leaf blade mostly linear and not petiolate at base, rarely with broad blades and stipitate (pseudo-petiole) at base (especially in Bambusoideae); ligules membranaceous or ciliate, rarely lacking (Echinochloa), margins of sheath of leaf connate at least at base. Inflorescences usually terminal, primarily paniculate, but secondarily extremely variable and transformed into racemes, spikes, digitate umbels, etc. Flowering unit (spikelet) usually with 2 bracteoles (glumes) at base; base occasionally with an obconical blunt to very acute thickening (callus). Flowers alternatingly along a central axis (rachilla) supported by a bract (lemma) and a prophyll (palea), bisexual or occasionally unisexual. Lemma and palea when falling as a unit clasping fruit at base often with an obconical blunt to very acute thickening (also called callus). Perianth usually composed of 2 or 3 minute scales (lodicules), rarely 6, sometimes absent (e.g. in sterile or female florets). Stamens usually 3, sometimes 6 (Bambusoideae), or 1 or 2; filaments filiform; anthers 2-locular. Pistil 1, superior; ovary and single anatropous ovule completely adnate; styles 2 or 3, apical or subapical, stigmas plumose. Caryopsis with rich endosperm; embryo basal, abaxial (facing lemma), opposite to punctiform to linear adaxial hilum (facing palea).

The Gramineae are one of the largest families of vascular plants with an estimated 620 genera and 10,000 species. Keng (1965) reported 201 genera and 775 species for mainland China. Hsu (1974) treated 5 subfamilies (excluding Bambusoideae), 27 tribes, 118 genera, 289 species, 1 subspecies, 39 varieties, and 8 forms in Taiwan.

The following arrangement of subfamilies, tribes and genera is that of Hsu (1978) with very few modifications. The descriptions of most genera are unchanged in this edition except that genera of the subfamily Pooideae (Festucoideae) which was mostly adopted from Clayton and Renvoize (1986). Some critical remarks were provided by Dr. J. F. Veldkamp, National Herbarium of the Netherlands, Leiden. Some line-drawings of Paniceae were drawed by Y. Fujimoto, Botanical Institute of Fujimoto, Kobe, Japan.

參考文獻

Thuarea 芻蕾草屬

作者

LIU, Ho-Yih

型態特徵

Perennials; culms solid, prostrate branching into numerous short erect flowering culms. Leaf blade small, expanded, Inflorescence a solitary, terminal, shortly pedicelate, short, spike-like secund raceme, before anthesis wrapped-up in uppermost leaf, consisting of very short sheath and spathaceous blade; rachis broad, convex, on hollow side with row of spikelets, lower 1-2 bisexual, upper 2-6 staminate. Bisexual spikelet 2-flowered, persistent; lower glume adaxial, minute, hyaline or 0; upper glume and lower lemma ca. equal, ovate-oblong, obtuse, thinly membranaceous, soft-hairy; lower palea membranaceous, 2-veined, often slitting deeply; lodicules 2, minute; stamens 3; upper palea and lemma thinly chartaceous, glabrous with hairy apex; upper lemma ovate-oblong, margins inrolled, 5-veined; upper palea 2-veined; lodicules and stamens like in lower floret; styles 2, free; stigma plumose, protruding apically. Staminate spikelets 2-flowered, articulate with knob shaped pedicel, soon deciduous after anthesis; lower glume adaxial, absent or minute and hyaline; upper glume and lower lemma ca. equal, oblong, obtuse, soft-hairy; lower palea thinly membranaceous, 2-veined, often deeply slit; stamens 3; upper palea oblong with broadly inflexed margins, soft-hairy at apex.

Two species, Madagascar to China and Polynesia. One species in Taiwan.

參考文獻

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