Buckwheat Family

Naked-stemmed Buckwheat © AFengler

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