Polygonum ramosissimum Michx.

Bushy Knotweed


CC = 5
CW = 3
MOC = 66

© DETenaglia

Family - Polygonaceae

Stems - From a taproot, herbaceous, erect to ascending or decumbent, multiple from base, branching, to +/-40cm long, terete, glabrous.

Leaves - Alternate, short-petiolate. Ocrea brownish, glabrous, +/-5mm long, usually lacerate at the apex. Petioles to +/-1mm long. Blades green to bluish-green, glabrous or with very few appressed hairs, entire, acute, oblong-elliptic, to +2cm long, +/-5mm broad.


© DETenaglia

Inflorescence - Axillary flowers, 1-3 per node. Flowers sessile or on pedicels to .5mm long, not exceeding the ocrea.

Flowers - Perianth segments green with white margins, rounded at apex, glabrous, .7mm broad, 2mm long. Outer 3 segments with more green than inner 3 segments, cupped and hooded at apex. Stamens 8, adnate at the base of the perianth segments. Filaments whitish-green, broadened at base, glabrous, .3mm long. Anthers yellow, .1mm broad. Ovary glabrous, 3-sided, 1mm long in flower, reddish near apex, mostly green. Styles 3, .2mm long, green, glabrous. Stigmas translucent, globose. Achenes rugose, 2mm long, 1.6mm broad, triangular, compressed and mostly 2-sided (3rd side not as broad as other 2).

Polygonum_ramosissimum_flowers.jpg Flowers.

© DETenaglia

Flowering - July - November.

Habitat - Open flood plains, alluvial soils near streams.

Origin - Native to the U.S.

Other info. - This little species has only been collected in a few counties in Missouri but is probably more common. The plant is easy to overlook because of its small size and inconspicuous flowers. Many of the small, ascending species of Polygonum are difficult to distinguish at first.

Photographs taken at the Current River Conservation Area, Reynolds County, MO., 7-29-01.