Distribution: Mostly centered in Northern and temperate parts of the World. The Texas flora includes 5 genera and 58 species with species of 4 genera endemic to the State.
Floral structure:
Significant features: Most species of this family, with the exception of the large genus Eriogonum (false buckwheat) show a unique vegetative feature at the node. A modified stipule encloses the node for form a sheathing structure known as an ocrea. The nodes also (like the Caryophyllaceae) tend to be swollen and this feature is signaled by the Genus name Polygonum which translates to 'many kneed', a reference to the swollen nodes. The flowers are small, perfect (usually) and either show a bi- or uniseriate calyx that often continues to develop after anthesis (accrescent) to produce a winged enclosure for the fruit, a trigonal (three-sided) or lenticular (lens shaped) achene.
Node of a sea grape (Coccoloba uvifera) with
ocrea
Eriogonum longifolium (the largest genus with 250 species)
- flowers
Rheum officinale from Kohler's
Medicinal Plants
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More information on the Polygonaceae
