Polygonum lapathifolium L.

Polygonum lapathifolium plant

Family - Polygonaceae

Stems - To 2m tall, glabrous.

Leaves - Alternate, glabrous, to 30cm long, 6cm wide, typically lanceolate, with impressed veins on the adaxial surface near the midrib. Ocrea not fringed with cilia and glabrous.

Polygonum lapathifolium leaves

Polygonum lapathifolium ocreaOcrea close-up.

Inflorescence - Terminal, loose, panicles and axillary racemes. Each flower cluster to 8cm long(tall), 3-9mm thick, nodding.

Flowers - Small(2-3mm long),  creamy white to slightly pinkish, dense in cluster.

Polygonum lapathifolium flowersClosed flowers.

Flowering - July - October.

Habitat - Moist soils, disturbed sites, gravel bars, roadsides, railroads.

Origin - Found in U.S. and Eurasia. Probably introduced in North America.

Other info. - This plant can get quite tall and is easily distinguished by the nodding racemes of the panicle. The leaves sometimes have a dark splotch in the center but this is not as common or pronounced as in the much smaller P. persicaria.

Photographs taken along the Current River, Shannon County, MO., 8-17-03.