Buckwheat Family

Polygonaceae (pol-i-go-NA-see-ee)

Iconic Features

• Swollen stem joints
• Dense clusters of tiny flowers
• Triangular seeds

Description (Jepson)

• Eudicotyledons (eudicots) – a major lineage of flowering plants including most plants traditionally described as dicots and generally characterized by
  • 2 seed leaves (dicotyledon)
  • Netted (reticulate) leaf venation
  • Flower parts in fours and fives
  • Pollen grains with 3 pores (tricolpate)
  • Vascular bundles in stem arranged in a ring
  • Taproot system
• Mostly herbaceous plants
  • Annuals, perennials, and shrubs
• Stem nodes (joints) often swollen
  • Generally with a scarious sheath around the stem
    • Formed by the fusion of papery stipules (leaf-like structures at the base of the leaf stalk), called ochrea
• Leaves
  • Simple (not divided into leaflets) and entire (with smooth edges)
  • Usually alternate (1 leaf at each junction with stem)
  • Attached to stem nodes or basal
  • Sometimes with papery stipules
• Flowers
  • Inflorescence (flower arrangement) in a variety of dense clusters
    • Sometimes held in cup- or vase-shaped bracts (modified leaves)
  • Tiny, generally bisexual, radially-symmetric flowers
    • 2-3 petals and 2-3 sepals (outer flower parts), in 2 separate whorls, similar in appearance and collectively called tepals
    • May be green, cream, white, yellow, pink, or red
      • Tepals often persist and age to red or brown
  • Ovary superior (above the attachment of other flower parts)
• Fruit is an achene (a single-seeded, dry fruit that does not split open), usually 3-angled
  • Sometimes with thin, flat margins (wings), which aid in dispersal by catching a ride on a breeze

Notes

• Approximately 1,200 species, mostly in the northern hemisphere
  • Includes rhubarb, docks, sorrels, and buckwheats
  • Many species adapted to high elevations and dry, cold climates
• Many species are astringent or highly toxic due to tannic and oxalic acids and anthraquinone glycosides
  • Stems of rhubarb (Reum rhabarbarum) are edible, but the leaves contain toxins, e.g. oxalic acid, which can cause kidney damage
• Buckwheats in the genus Fagopyrum have been cultivated for thousands of years for use as pseudocereals
  • Common crop in the US before nitrogen fertilizer in the 20th century allowed corn and wheat to become dominant (Myers 2018)
  • Flour used for noodles, like soba, in many Asian cuisines and for traditional Russian blinis, French crepes, and Dutch pancakes
  • Hulled, unground seeds, a type of groats, are used for porridge
  • Accommodate some dietary or cultural restrictions that prohibit the eating of wheat
• Scientific name from the Greek poly, “many,” and gónato, “knee,” referring to the swollen stem nodes (joints) characteristic of this family
• Common name from Old English for “beech-wheat”
  • 3-sided seeds resemble beechnuts
  • Though not related to wheats, which are in the Grass family, the seeds of some buckwheats are ground into meal or flour
  • Also known as the Knotweed family
• Represented by 11 species at Edgewood

See General References

Specific References

Myers, R. 2018, Dec. Growing buckwheat for grain or cover crop use. Extension: University of Missouri.

Browse Some Edgewood Plants in this Family