Polygonaceae
(Knotweed/Buckwheat Family)
Habit
- herbs or shrubs
Leaves
-
alternate,
opposite or
whorled or
basal,
some have
sheathing stipules (membrane called a
ocrea)
Inflorescence
- various often
racemes or
umbels
Flowers
-
perfect,
regular, sometimes
subtended by a
calyx-like
involucre
Sepals
- often 6 in 2 series, traditionally treated as
sepals
Petals
- absent
Stamens
- 3-9,
free
Ovary
-
superior, of 2-3
carpels with 1
locule and 1
basal
ovule
Fruit
- a lens-shaped or triangular
achene
Diversity
- 30 genera / 1000 species
Distribution
- most in Northern Hemisphere; many in western North America
Economics
- rhubarb
(petioles of Rheum--other parts poisonous);
achenes of Fagopyrum ground to make buckwheat flour;
some cultivated ornamentals (Queen's wreath--Antigonon)
Notes
-
Images
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