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29. Indosasa McClure, Lingnan Univ. Sci. Bull. 9: 28. 1940.
大节竹属 da jie zhu shu
Authors: Zheng-de Zhu & Chris Stapleton
Arborescent bamboos, sometimes shrubby. Rhizomes leptomorph, with running underground stems. Culms diffuse, erect to nodding; internodes substantially grooved above branches; wall thick, cavity with granular or spongy pith; nodes prominent. Mid-culm branches 3, subequal or central dominant. Culm sheaths deciduous, leathery or thickly papery, setose; ligule truncate; blade large, triangular or lanceolate, rarely strap-shaped. Leaves usually medium to large-sized, transverse veins distinct. Inflorescence fully bracteate, partially iterauctant, lateral, racemose, sessile, prophyllate. Spikelets many flowered, gradually enlarged; basal bracts and glumes often with basal axillary buds developed into secondary spikelets; basal 1–4 florets sometimes sterile. Glumes usually 2; lemma larger and broader than glumes, many veined; palea obtuse, 2-keeled; lodicules 3, subequal. Stamens 6; filaments free. Ovary narrowly ellipsoid or fusiform; style short; stigmas 3, plumose. Fruit a caryopsis, ovoid to ellipsoid, beaked. New shoots spring–early summer.
About 15 species: S China, N Vietnam; 15 species (13 endemic) in China.
Indosasa is the only genus of bamboos in China with six stamens, bracteate inflorescences, and leptomorph rhizomes. In addition to the species treated below, Indosasa jinpingensis T. P. Yi (J. Bamboo Res. 20(4): 1. 2001) was described from Yunnan (Jinping). In the protologue it was compared with I. parvifolia. Indosasa hispida (species no. 13) could not be included in the following key because its culm sheaths are unknown.
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| 1 |
Culm sheaths without auricles |
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(2) |
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Culm sheaths with auricles |
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(9) |
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| 2 (1) |
Culm internodes initially glabrous |
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(3) |
| + |
Culm internodes initially pubescent or scabrous |
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(6) |
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| 3 (2) |
Culm sheaths asymmetrical, central parts of sheath densely setose; culm wall thick, internodes nearly solid at culm base. |
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1 I. crassiflora |
| + |
Culm sheaths symmetrical, sparsely setose or subglabrous; culm wall thin |
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(4) |
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| 4 (3) |
Culm branch nodes weakly prominent; ultimate branches usually with 1 leaf, rarely 2-leaved with apical blade inverted. |
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2 I. acutiligulata |
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Culm branch nodes very prominent; ultimate branches 2–4-leaved, without apical blade inverted |
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(5) |
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| 5 (4) |
Culms to 3 m; culm sheaths with oral setae absent or, if present, culms initially white hairy. |
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3 I. glabrata |
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Culms to 5 m; culm sheaths with oral setae present, 5–10 mm; culms glabrous. |
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15 I. triangulata |
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| 6 (2) |
Culm nodes and branch nodes weakly prominent; leaf blade abaxially pubescent. |
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4 I. angustata |
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Culm nodes and branch nodes strongly prominent; leaf blade usually glabrous |
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(7) |
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| 7 (6) |
Culm internode cavity pith lamellate; internodes initially villous; culm sheath sometimes with sparse oral setae. |
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3 I. glabrata |
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Culm internode cavity pith spongy or granular, never lamellate; internodes initially setose; culm sheath without oral setae |
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(8) |
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| 8 (7) |
Culm internode pith spongy; leaf blade 10–17 × 2–2.5 cm. |
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5 I. spongiosa |
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Culm internode pith slightly granular; leaf blade 14–27 × 2.5–4.5 cm. |
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6 I. ingens |
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| 9 (1) |
Ultimate branches with 1 leaf, rarely 2 leaves with apical leaf blade inverted. |
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2 I. acutiligulata |
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Ultimate branches with 2–9 leaves, apical leaf blade not inverted |
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(10) |
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| 10 (9) |
Culm nodes and branch nodes moderately prominent; culm sheaths sparsely setose |
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(11) |
| + |
Culm nodes and branch nodes very prominent (slightly prominent in I. patens); culm sheaths with clumped setae |
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(12) |
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| 11 (10) |
Culms initially setose; culm sheaths with brown setae; leaf blade glabrous. |
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11 I. longispicata |
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Culms glabrous; culm sheaths with retrorse, purple-brown setae; leaf blade abaxially pubescent |
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12 I. gigantea |
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| 12 (10) |
Culm sheaths glaucous. |
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14 I. singulispicula |
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Culm sheaths not glaucous |
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(13) |
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| 13 (12) |
Culm sheaths yellow-green or yellow; blade marginally never undulate |
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(14) |
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Culm sheaths red-brown, purple-brown or brown; blade marginally undulate or not |
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(15) |
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| 14 (13) |
Culm internodes glaucous, culm sheath auricles minute; leaf blade 11–22 × 1.5–3 cm. |
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7 I. sinica |
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Culm internodes not glaucous; culm sheath auricles large, projecting, rounded; leaf blade 6–14 × 1–1.5 cm. |
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8 I. parvifolia |
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| 15 (13) |
Culm sheath blade marginally not undulate, entire, glabrous; branches horizontal; leaf blade 15–25 × 2–4 cm, abaxially sparsely pubescent. |
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9 I. patens |
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Culm sheath blade marginally undulate, denticulate, setose; branches deflexed; leaf blade 8–15 × 1–2.3 cm, abaxially glabrous. |
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10 I. lipoensis |
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List of lower taxa
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