Polygonum convolvulus L. - Black Bindweed

Polygonum convolvulus plant

Family - Polygonaceae

Stems - Twining, herbaceous, to +1m long, angled or ribbed, retrorse strigose on angles and ribs, often reddish in strong sun, branching, multiple from base.

Leaves - Alternate, petiolate. Petioles with a deep adaxial groove, retrorse strigose, to +2cm long. Blades sagittate, acute to acuminate, entire, glabrous, strigillose on the margins, to +4cm long, +3cm broad.

Polygonum convolvulus leaves

Inflorescence - Axillary and terminal flowers. Axillary flowers typically single or paired. Terminal flowers in bracteate racemes, in whorls of 4 at each node of the raceme, often subtended by reduced foliaceous bracts. Axis of racemes retrorse strigillose. Pedicels reddish in strong sun, 1-2mm long, mostly glabrous.

Polygonum convolvulus inflorescence

Flowers - Perianth greenish and often with whitish or pinkish apical margins, quickly expanding in size to 4mm long (1-2mm in flower). Stamens 6-8. Anthers pinkish, bilobed, .3mm broad. Filaments short, white, glabrous, .5mm long. Ovary superior, green, glabrous, 3-angled, .7mm long in flower. Style short, green, glabrous, .1mm long. Stigma green, capitate, .1-.2mm broad. Seeds dull black but shiny on the angles, 3-angled, to 3mm long.

Polygonum convolvulus flowersFlowers.

Polygonum convolvulus seedsSeeds.

Flowering - May - September.

Habitat - Waste ground, disturbed sites, open woods, roadsides, railroads.

Origin - Native to Europe.

Other info. - This species can be found throughout Missouri and is becoming more common. It spreads very quickly.
The leaves and habit of the plant resembles those of the genus Convolvulus, hence the species epithet.
Steyermark wrote that natives used to grind the seeds and make flour.

Photographs taken off Hwy H, Shannon County, MO., 7-18-03.


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