Botanical Family · Caryophyllales

Polygonaceae

Buckwheat/Knotweed family

14 speciesOrder Caryophyllales8+ well-known plants

Herbs and shrubs with characteristic membranous sheaths (ochrea) at each node. Includes buckwheat, sorrel, dock, and Japanese knotweed.

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Representative specimen · Polygonaceae

Key pattern

Alternate leaves wrapped at the base by a papery, sheath-like stipule (ochrea) hugging the stem at each node; small flowers lack true petals, their colour coming from a persistent calyx instead, and ripen into a three-angled achene.

The papery nodal sheath (ochrea) is diagnostic for the whole family, and tissues in several genera are rich in oxalic acid or tannins, giving a characteristically sour or astringent taste.

Identify the species

Which Polygonaceae species is this?

Answer what you can see and narrow it down to a single Polygonaceae species.

Click a node to trace its path · pinch or scroll to zoom · drag to pan

Leaf ShapeWhat is the overall shape of the leaf blade?

Cordate

Lanceolate

Lanceolate (long, narrow, tapering to a point)

Linear (long and narrow, parallel sides)

Orbicular (round)

Ovate (egg-shaped, broad at base)

Sagittate

Sagittate (arrowhead-shaped)

HabitWhat is the plant's growth habit?

Climbing vine

Herb

How to recognise the Polygonaceae family

01
Leaf arrangement: alternate
02
Leaf type: simple
03
Growth forms: herb/shrub/vine
04
Inflorescence: spike/raceme/panicle
05
Fruit: trigonous achene

Family identification method

To check whether a plant belongs to Polygonaceae, compare the leaf arrangement, leaf type, flower symmetry, fruit type, and one distinctive marker together. A single feature can mislead; the family pattern is the combination.

Learn the full family-identification method