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12. Rheum Linnaeus, Sp. Pl. 371. 1753; Gen. Pl. ed. 5. 174: 1754; Boiss., Fl. Or. 4: 1003. 1879; Hook.f., Fl. Brit. Ind. 5:55. 1886; Losinsk. in Kom., Fl. URSS 5: 482. 1936; D.A.Webb inTutin et al., Fl. Europ. 1: 82. 1964; Cullen in P.H.Davis, Fl. Turk. 2: 268. 1967; Rech.f. & Schiman-Czeika in Rech.f., Fl. Iran. 56:25. 1968; Grierson & D.G.Long, Fl. Bhutan 1(1): 171. 1983; Munshi & Javeid, Syst. Stud. Polygon. Kashm. Himal. 85. 1986; Chaudhary, Fl. King. Saudi Arab. 1: 308. 1999.
Perennial herbs or undershrubs with thick rhizomes. Stem solid or fistular, smooth or furrowed, glabrous or pubescent or plant acaulescent. Leaves often very large, forming a basal rosette, simple, reniform, palmately veined, entire, toothed or lobed. Ochreae scarious. Inflorescence a panicle or spike-like with the flowers born in clusters. Flowers bisexual; pedicels articulate. Perianth segments 6 in 2 whorls, distinct or connate at base, equal or outer whorl usually slightly larger, not accrescent. Stamens mostly 9, rarely 6, borne on a ring adnate to the perianth. Ovary (2-) 3 (-4)-angled; stigmas 3, capitate, styles very short. Fruit 3-angled, 2-4-winged, wings varying in size and colour. Seeds with broad cotyledons and straight embryo.
A genus with about 50 species, distributed in temperate and subtropical Asia. In Pakistan it is represented by 6 species.
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| 1 |
Plants without distinct stem. Leaves all basal. |
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(2) |
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Plants with distinct stem. Leaves basal and cauline both or stem leafless. |
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(3) |
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| 2 (1) |
Flowers in leafless panicles. Fruits nearly orbicular, notched at both ends. |
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4 R. tibeticum |
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Flowers in spike-like racemes. Fruits ellipsoid not notched at both ends. |
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3 R. spiciforme |
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| 3 (1) |
Flowers in fascicles. |
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2 R. ribes |
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Flowers in panicles. |
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(4) |
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| 4 (3) |
Flowers white-pink or pale yellowish. Basal leaf blade up to 50 cm long but never exceeding; upper surface glabrous or papillose. |
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(5) |
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Flowers dark purple. Basal leaf blade up to 60 cm long; upper surface somewhat scabrous above. |
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1 R. australe |
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| 5 (4) |
Fruits 13-15 mm across. Flowers white to pink. |
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6 R. wittrockii |
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Fruits 8-10 mm across. Flowers pale yellowish. |
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5 R. webbianum |
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Lower Taxa
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Treatments in Other Floras @ www.efloras.org
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