Polygonaceae: Buckwheat Family. Identify plants and flowers.

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Polygonaceae: Buckwheat Family Plant Identification Characteristics.

Polygonaceae
Plants of the Buckwheat Family

The Buckwheat family is as familiar as rhubarb or sorrel. If you grow either of these plants in your garden, then be sure to look at the flowers and seeds. The Buckwheats have simple, toothless leaves and often swollen joints, or nodes, on the stems, plus lots of small flowers in clusters or spikes. The Latin "Polygonum" literally means "many knees", and refers to the swollen nodes of the leaf stems. There are typically 5 or 6 sepals, sometimes colored like petals and often in two layers, but no true petals, and 3 to 9 stamens. The ovary is positioned superior and consists of 3 united carpels (syncarpous), forming a single chamber. It matures as a dry seed, usually brown or black and triangular or lens-shaped, sometimes with wings. Worldwide, there are about 40 genera and 800 species, including 15 genera in North America. Sour juice, from oxalic acid, is common in this family. Many plants of this family also contain tannic acid and anthraquinone glycosides.

Key Words: Small flowers with colored sepals, no petals and often triangular seeds.

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Eriogonum flavum. Yellow Wild Buckwheat.	Eriogonum flavum. Yellow Wild Buckwheat.
Eriogonum sp. Wild Buckwheat.	Eriogonum sp. Wild Buckwheat.
Polygonum bistortoides. American Bistort.	Polygonum bistortoides. American Bistort.
Oxyria digyna. Mountain Sorrel. Tobacco Root Mountains. Pony, Montana.	Oxyria digyna. Mountain Sorrel. Seven Devils Mountains, Idaho.
Polygonum amphibium. Water Smartweed.	Polygonum amphibium. Water Smartweed. Harrison Lake. Near Harrison, Montana.
Rheum rhaponticum. Rhubarb. Rhubarb was often planted around old-time cabins. In many places the cabins are all gone, but the rhubarb is still growing. Tobacco Root Mountains. Pony, Montana.	Rumex hymenosepalus. Canaigre. Arizona
Rumex acetosella. Sheep Sorrel.	Rumex acetosella. Sheep Sorrel.
Rumex crispus. Curly Dock.	Rumex crispus. Curly Dock. Tobacco Root Mountains. Pony, Montana.
Rumex venosus. Veiny Dock.	Rumex venosus. Veiny Dock.