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52. Achnatherum P. Beauvois, Ess. Agrostogr. 19, 146. 1812.
芨芨草属 ji ji cao shu
Lasiagrostis Link; Stipa sect. Lasiagrostis (Link) Hackel; Timouria Roshevitz.
Perennials, usually tussocky. Leaf blades linear to setaceous, flat or rolled. Inflorescence an open or contracted panicle, sometimes almost spikelike. Spikelets with 1 floret, bisexual, disarticulating above glumes; rachilla extension absent; glumes lanceolate to elliptic-oblong, subequal or slightly unequal, a little longer than floret, membranous, 1–3(–5)-veined, apex obtuse to acuminate; callus short, obtuse or acute, not pungent, shortly bearded; lemma lanceolate, terete, usually papery, sometimes becoming somewhat indurate at maturity, 3–5-veined, pilose, margins typically approximate, sometimes overlapping, apex shortly 2-toothed, awned from between teeth; awn persistent or deciduous, straight or 1(or 2)-geniculate with twisted column, scabrid throughout or column minutely hairy; palea midline often exposed between lemma margins. Lodicules 3, lanceolate. Stamens 3, anthers often with hair tufts at apex. Stigmas 2.
About 50 species: N Africa, Europe eastward to Japan, North America; 18 species (six endemic) in China.
Achnatherum is sometimes included within a more broadly defined Stipa, mainly because of the difficulty in placing the group of species around A. sibiricum, which are intermediate in their characteristics. Some species, including A. inebrians, are poisonous to livestock.
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| 1 |
Awn straight or slightly curved, without obvious column, very indistinctly twisted below, usually falling early |
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(2) |
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Awn clearly geniculate with twisted column, persistent (caducous in A. psilantherum) |
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(9) |
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| 2 (1) |
Leaf blades 1–2 cm wide; glumes 7–9-veined. |
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1 A. coreanum |
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Leaf blades 0.1–1 cm wide; glumes 1–3-veined |
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(3) |
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| 3 (2) |
Culms usually more than 1 m; ligule of culm leaves 5–17 mm |
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(4) |
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Culms less than 1 m; ligule of culm leaves 0.2–1 mm |
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(5) |
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| 4 (3) |
Lemma pilose throughout; awn 0.5–1.2 cm. |
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2 A. splendens |
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Lemma pilose along lateral veins; awn 0.2–0.4 cm. |
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3 A. breviaristatum |
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| 5 (3) |
Panicle spikelike, 4–7 cm; glumes keeled; awn ca. 0.4 cm. |
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4 A. saposhnikovii |
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Panicle open or contracted, 7–30 cm; glumes rounded on back; awn 0.4–2 cm |
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(6) |
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| 6 (5) |
Lemma pubescent below, a conspicuous tuft of longer hairs below apex; awn 1.5–2 cm. |
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5 A. inaequiglume |
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Lemma evenly pubescent; awn 0.4–1.2 cm |
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(7) |
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| 7 (6) |
Ligule 0.5–1 mm. |
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6 A. caragana |
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Ligule 0.1–0.2 mm or absent |
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(8) |
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| 8 (7) |
Densely tufted, without rhizome; leaf blades 1–2 mm wide; branches of panicle 2 per node; awn 0.4–0.8 cm. |
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7 A. chinense |
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Loosely tufted, shortly rhizomatous; leaf blades 3–10 mm wide; branches of panicle 3–4 per node; awn 0.8–2 cm. |
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8 A. henryi |
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| 9 (1) |
Culms slender, less than 1 m tall, 1–1.5 mm in diam.; leaf blades usually rolled, 0.5–2(–4) mm wide |
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(10) |
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Culms fairly robust, up to 1.5 m tall, 1.5–4 mm in diam.; leaf blades often flat, 2–10 mm wide |
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(14) |
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| 10 (9) |
Spikelets 7.5–14 mm; lemma pilose below middle; awn with pubescent column |
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(11) |
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Spikelets 5–7 mm; lemma pilose throughout; awn scabrid throughout |
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(12) |
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| 11 (10) |
Anthers 2–2.5 mm, often glabrous. |
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9 A. chingii |
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Anthers 2.8–4.5 mm, bearded. |
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10 A. duthiei |
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| 12 (10) |
Panicle contracted, branches suberect, spiculate to base |
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(13) |
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Panicle lax, branches spreading, bare in lower part; awn 1–1.5 cm. |
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13 A. nakaii |
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| 13 (12) |
Awn 2–3 cm, persistent; anthers 2.8–3.5 mm. |
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11 A. jacquemontii |
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Awn 1.5–1.8 cm, caducous; anthers 2–2.5 mm. |
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12 A. psilantherum |
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| 14 (9) |
Lemma 4–4.2 mm; panicle densely contracted, spikelike. |
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14 A. inebrians |
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Lemma 4.5 mm or more; panicle open or contracted |
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(15) |
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| 15 (14) |
Leaf sheaths scabrid; culms scabrid below panicle; leaf blades pubescent; glumes puberulous. |
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15 A. pubicalyx |
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Leaf sheaths smooth; culms smooth; leaf blades smooth or scabrid; glumes glabrous, smooth or asperulous |
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(16) |
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| 16 (15) |
Panicle densely contracted, branches with spikelets to base; leaf blades often convolute, 0.3–0.7 mm wide; callus acute, 0.5–1 mm. |
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16 A. sibiricum |
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Panicle open or loosely contracted, branches often bare below middle; leaf blades flat, up to 1 cm wide; callus obtuse, 0.3–0.5 mm |
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(17) |
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| 17 (16) |
Awn 20–25 mm. |
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17 A. pekinense |
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Awn 10–18 mm. |
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18 A. brandisii |
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List of lower taxa
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