Polygonum persicaria L.

Polygonum persicaria plant

Family - Polygonaceae

Stems - To -1m tall, glabrous, branching at base, erect, herbaceous, from taproot, typically reddish at nodes.

Leaves - Alternate, lanceolate to linear lanceolate, short-petiolate to sessile above, to +11cm long, +/-2cm broad, glabrous to sparse appressed pubescent, typically with purple splotch near middle of blade, entire. Ocrea appressed pubescent friged with cilia. Petioles to 6mm long, red, sparse appressed antrorse pubescent.

Polygonum persicaria seedlingYoung plant.

Polygonum persicaria leavesLeaves.

Inflorescence - Terminal and axillary racemes +3cm long, +/-1cm in diameter, dense. Bracts subtending flowers (ocreolae) with or without short cilia (-1mm) at summit.

Flowers - Perianth pink to rose or typically whitish at anthesis, to 3.5mm long. Perianth parts glabrous, ovate to orbicular. Stamens 5, 1.7mm long, white, glabrous, adnate to base of perianth parts. Anthers pale yellow to white, .1mm broad. Styles typically 2, .8mm long, white, glabrous. Achenes typically 2-sided, black, shiny, to +/-2mm long.

Polygonum persicaria flowers

Flowering - May - October.

Habitat - Moist to wet waste ground, disturbed sites, meadows, streambanks, roadsides, railroads.

Origin - Native to Europe.

Other info. - This species is recognized by the characteristic purple splotch in the center of the leaf. The spot is not always present but typically is. The perianth is somewhat variable in color.
The plant is common in the habitats mentioned above and is somewhat toxic.
This species somewhat resembles P. cespitosum Bl. but the latter has a more rose-colored perianth and the bracts of the inflorescence have cilia which typically are longer than the flowers.

Photographs taken at the Kansas City Zoo, 5-30-99 and 5-11-00.


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