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16. Zeuxine Lindley, Orchid. Scelet. 9. 1826.
线柱兰属 xian zhu lan shu
Authors: Xinqi Chen, Stephan W. Gale, Phillip J. Cribb & Paul Ormerod
Haplochilus Endlicher; Heterozeuxine T. Hashimoto; Monochilus Wallich ex Lindley; Psychechilos Breda; Strateuma Rafinesque; Tripleura Lindley.
Herbs, terrestrial or rarely lithophytic. Rhizome usually elongate, creeping, fleshy, several noded; roots emerging from rhizome nodes, cylindric, stout. Stem erect or ascending, terete, leafy, glabrous. Leaves cauline or subrosulate, withered or pendulous at anthesis in some species, adaxially green to blackish, sometimes with a white stripe along midvein, linear-lanceolate, obliquely ovate-lanceolate, or elliptic, with or without a petiole-like base sheathing stem, sometimes slightly fleshy. Inflorescence glabrous or pubescent, with a few crowded to scattered sheathing bracts and a few to many flowers in a short to elongate terminal raceme; floral bracts usually equal in length to pedicel and ovary. Flowers resupinate or occasionally erect, small, not opening widely; ovary twisted, glabrous or pubescent. Sepals free, similar, outer surface glabrous to pubescent; dorsal sepal concave, forming a hood with petals; lateral sepals enclosing base of lip. Petals connivent with dorsal sepal, nearly as long as dorsal sepal though usually narrower; lip usually adnate to column margin at base, 2- or 3-partite or rarely entire; hypochile concave-saccate to cymbiform, containing 1 to a few scalelike, subulate or lamellate calli on each side at base; mesochile (when present) short, margin often involute and forming a tube, externally glabrous or pubescent and sometimes with a lamellate flange on each side; epichile dilated, entire to 2-lobed. Column short, dilated, with or without a pair of lateral wings; anther ovoid, 2-locular; pollinia 2, each longitudinally parted, granular-farinaceous, sectile, attached either directly to viscidium or via a short tegula; viscidium ligulate-lanceolate to ovate; rostellum conspicuous, erect, bifid; stigma lobes separate, convex, lateral or at apical corners of column. Capsule erect.
About 80 species: tropical and S Africa, through tropical and subtropical Asia, to New Guinea, NE Australia, and the SW Pacific islands; 14 species (two endemic) in China; two additional species (both endemic) are incompletely known.
This is a taxonomically complex group and further analysis of collections from throughout Asia is necessary before nomenclatural stability can be achieved.
Incompletely known species
Zeuxine niijimae Tatewaki & Masamune, Bot. Mag. (Tokyo) 46: 772. 1932 ["niijimai"].
眉原线柱兰 mei yuan xian zhu lan
Plants ca. 20 cm tall, slender. Rhizome ascending. Stem 2-leaved. Leaves ovate-lanceolate, slightly oblique, ca. 2.5 × 1.5 cm, membranous, base rounded, apex acute; petiole-like base ca. 0.7 cm including tubular sheath. Rachis ca. 2 cm, 2- or 3-flowered; floral bracts ovate-lanceolate, ca. as long as ovary, apex acuminate. Flowers small. Dorsal sepal ovate, concave, ca. 6 mm, apex acuminate; lateral sepals obliquely ovate, ca. 5 × 2 mm, 1- or 3-veined, apex obtuse. Petals ovate-deltoid, ca. 5 × 2.5 mm, apex acute; lip Y-shaped, ca. 4 mm; epichile 2-lobed; lobes obliquely orbicular, ca. 2 × 1.5 mm. Column ca. 2 mm. Fl. Apr.
● C Taiwan.
Zeuxine kantokeiensis Tatewaki & Masamune, Bot. Mag. (Tokyo) 46: 772. 1932.
关刀溪线柱兰 guan dao xi xian zhu lan
Plants ca. 30 cm tall, slender. Leaves withered at anthesis. Inflorescence 9-21 cm, pubescent, with a few sterile bracts; sterile bracts ovate-deltoid, ca. 10 × 3 mm, apex acuminate; rachis 3-9 cm; floral bracts ovate, ca. 4 × 2 mm, apex acute-acuminate. Flowers sublaxly arranged, small; ovary ovoid, ca. 3 mm including pedicel. Dorsal sepal ovate, concave, ca. 3 mm, outer surface pubescent, 1-veined, apex acute to obtuse; lateral sepals obliquely ovate, ca. 2 × 1 mm, 3-veined, apex acute to obtuse. Petals oblong, ca. 2 × 1 mm, glabrous, apex obtuse; lip T-shaped; epichile 2-lobed; lobes ca. 1.3 × 1 mm, apex obtuse. Column ca. 1 mm; rostellum arms linear, ca. 1 mm. Fl. Apr.
● C Taiwan.
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| 1 |
Leaves linear to linear-lanceolate, not stalked, base directly sheathing stem |
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(2) |
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Leaves ovate-lanceolate to elliptic, base contracted into a petiole-like stalk sheathing stem |
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(3) |
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| 2 (1) |
Plants 4-24 cm tall; ovary and sepals glabrous. |
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1 Z. strateumatica |
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Plants 20-35 cm tall; ovary and sepals pubescent. |
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2 Z. membranacea |
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| 3 (1) |
Lip entire, rhombic, not adnate to column, base contracted and lacking calli. |
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3 Z. integrilabella |
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Lip 2- or 3-partite, base adnate to column, hypochile concave and containing 2 or more subulate, lamellate, or 2- or 3-digitate calli near base |
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(4) |
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| 4 (3) |
Epichile of lip transversely dilated but as broad as or narrower than hypochile, entire to shallowly 2-lobed |
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(5) |
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Epichile of lip dilated, broader than hypochile, distinctly 2-lobed |
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(7) |
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| 5 (4) |
Ovary sparsely hairy; sepals hairy abaxially. |
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5 Z. philippinensis |
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Ovary glabrous; sepals glabrous |
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(6) |
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| 6 (5) |
Leaves with a white line along midvein; inflorescence subdensely flowered; lip with a much-reduced mesochile; mesochile margin membranous, glabrous. |
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4 Z. goodyeroides |
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Leaves lacking a white line along midvein; inflorescence laxly flowered; lip lacking a mesochile, apical margin of hypochile fleshy, papillose. |
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6 Z. agyokuana |
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| 7 (4) |
Plants robust, 30-50 cm tall; leaves 5-12 × 3-7 cm; lateral sepals 8-9 mm. |
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7 Z. odorata |
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Plants slender to somewhat stout, to 35 cm tall; leaves 2-6 × 1-3 cm; lateral sepals 3-7.5 mm |
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(8) |
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| 8 (7) |
Midvein of leaves marked with silvery blotches or a white line (also on lateral veins in Z. gengmanensis); leaves not usually withering at anthesis |
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(9) |
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Leaves uniformly green or occasionally tinged with red, withering and pendulous at anthesis |
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(10) |
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| 9 (8) |
Stem stout, ca. 5 mm in diam.; lateral veins of leaves marked with white lines; flowers pink; hypochile containing 2 short, rounded calli. |
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8 Z. gengmanensis |
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Stem slender, 1-2 mm in diam.; lateral veins of leaves without white lines; flowers white or pale yellow; hypochile containing 2 2- or 3-digitate to narrowly lamellate calli. |
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9 Z. nervosa |
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| 10 (8) |
Lip T-shaped; epichile lobes diverging at right angles to axis of lip |
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(11) |
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Lip Y-shaped; epichile lobes diverging at acute angles to axis of lip; epichile not mucronate at apex |
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(12) |
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| 11 (10) |
Lip white. |
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10 Z. parvifolia |
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Lip saffron. |
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11 Z. flava |
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| 12 (10) |
Lip 7-9 mm; hypochile containing 2 lamellate calli, each often with a linear extension; epichile lobes 3-5.5 mm; column wings lacking. |
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12 Z. grandis |
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Lip to 6 mm; hypochile containing 2 subulate, hooked calli; epichile lobes 2-3 mm; column with triangular or transversely oblong wings |
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(13) |
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| 13 (12) |
Lip straight, or epichile rotated gently downward; epichile lobes obovate-flabellate, 2-2.5 × 2-2.2 mm. |
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13 Z. affinis |
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Epichile reflexed sharply downward from apex of mesochile; epichile lobes oblong to irregularly rhombic, 2.5-3 × 1.2-1.8 mm. |
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14 Z. reflexa |
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List of lower taxa
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