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Polygonaceae A. L. Jussieu

蓼科 liao ke

Authors: Anjen Li, Bojian Bao, Alisa E. Grabovskaya-Borodina, Suk-pyo Hong, John McNeill, Sergei L. Mosyakin, Hideaki Ohba & Chong-wook Park

Oxyria sinensis

Credit: Harvard University Herbaria

Herbs, shrubs, or small trees, sometimes monoecious or dioecious. Stems erect, prostrate, twining, or scandent, often with swollen nodes, striate, grooved, or prickly. Leaves simple, alternate, rarely opposite or whorled, petiolate or subsessile; stipules often united to a sheath (ocrea). Inflorescence terminal or axillary, spicate, racemose, paniculate, or capitate. Pedicel occasionally articulate. Flowers small, actinomorphic, bisexual, rarely unisexual. Perianth 3-6-merous, in 1 or 2 series, herbaceous, often enlarged in fruit or inner tepals enlarged, with wings, tubercles, or spines. Stamens usually (3-)6-9, rarely more; filaments free or united at base; anthers 2-loculed, opening lengthwise; disk annular (often lobed). Ovary superior, 1-loculed; styles 2 or 3, rarely 4, free or connate at lower part. Fruit a trigonous, biconvex, or biconcave achene; seed with straight or curved embryo and copious endosperm.

About 50 genera and 1120 species: worldwide, but primarily N temperate with a few species in tropical regions; 13 genera (two endemic) and 238 species (65 endemic) in China.

All Chinese genera belong to the Polygonoideae, a subfamily of some 790 species defined by the presence of ocreae, a monopodial branching pattern, and the lack of an involucre. The Eriogonoideae (330 species) are found only in the New World.

Chinese genera of economic importance include Rheum, which has medicinal uses and is also a food plant (rhubarb) in many other regions, and Fagopyrum, which produces a grain (buckwheat).

Fallopia nervosa Loureiro is Microcos paniculata Linnaeus (Tiliaceae).

Li Anjen, Kao Tsoching, Mao Zumei & Liu Yulan. 1998. Polygonaceae. In: Li Anjen, ed., Fl. Reipubl. Popularis Sin. 25(1): 1–209.


1 Shrub, rarely a subshrub.   (2)
+ Annual or perennial herb.   (7)
       
2 (1) Leaves small, scaly; stamens 12-18; styles 4.   8 Calligonum
+ Leaves large, not scaly; stamens 6-8; styles 2 or 3.   (3)
       
3 (2) Tepals 6; stigmas penicillate.   12 Rumex
+ Tepals 5; stigmas capitate.   (4)
       
4 (3) Achenes with wings.   10 Parapteropyrum
+ Achenes without wings.   (5)
       
5 (4) Stems twining.   3 Fallopia
+ Stems erect.   (6)
       
6 (5) Tepals: inner 3(or 2) enlarged in fruit.   9 Atraphaxis
+ Tepals not enlarged in fruit.   2 Polygonum
       
7 (1) Achenes with wings.   (8)
+ Achenes without wings.   (10)
       
8 (7) Tepals 4; achenes biconvex, margin with wings.   11 Oxyria
+ Tepals 5 or 6; achenes trigonous, angles with wings.   (9)
       
9 (8) Tepals 5; achenes 3-horned at base; stems scandent.   7 Pteroxygonum
+ Tepals 6; achenes not horned at base; stems erect.   13 Rheum
       
10 (7) Tepals 3.   1 Koenigia
+ Tepals 5 or 6, rarely 4.   (11)
       
11 (10) Tepals 6, rarely 4, stigmas penicillate.   12 Rumex
+ Tepals 5, rarely 4; stigmas capitate or fimbriate.   (12)
       
12 (11) Styles 2, persistent, indurate, elongate in fruit, hooked at apex.   5 Antenoron
+ Styles 3, rarely 2, usually deciduous, neither indurate nor elongate in fruit, never hooked at apex.   (13)
       
13 (12) Stems twining or erect, tepals: outer 3, enlarged in fruit, abaxial surface with wings or keels, rarely not enlarged, without wings or keels.   (14)
+ Stems erect; tepals not enlarged in fruit, rarely enlarged, becoming fleshy.   (15)
       
14 (13) Stems twining; flowers bisexual; stigmas capitate.   3 Fallopia
+ Stems erect; flowers unisexual, plant dioecious; stigmas fimbriate.   4 Reynoutria
       
15 (13) Achenes trigonous, much longer than or rarely equaling persistent perianth.   6 Fagopyrum
+ Achenes trigonous or biconvex, shorter than or rarely longer than persistent perianth.   2 Polygonum

  • List of lower taxa


     

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