[Knotweeds: The Genera Aconogonon, Bistorta, Fallopia, Persicaria and Polygonum in Mt. Adams Country]

American Bistort, Snakeweed, Mountain Meadow Knotweed, Western Bistort

Bistorta bistortoides

Synonyms: Persicaria bistortoides, Polygonum bistortoides, Polygonum bistortoides var. linearifolium, Polygonum bistortoides var. oblongifolium, Polygonum cephalophorum, Polygonum glastifolium, Polygonum vulcanicum

Inflorescence of American Bistort, Snakeweed, Mountain Meadow Knotweed, Western Bistort: Bistorta bistortoides (Synonyms: Persicaria bistortoides, Polygonum bistortoides, Polygonum bistortoides var. linearifolium, Polygonum bistortoides var. oblongifolium, Polygonum cephalophorum, Polygonum glastifolium, Polygonum vulcanicum)

The photo above shows a close-up of the flower head of american bistort as seen along the Yakima-Klickitat county line at the southeast side of Mt. Adams.........May 29, 2006.

Characteristics:

American bistort is an erect perennial arising 30-60 cm from a thick tuber. The basal leaves are long petiolate and not jointed to the stem. The leaf blade is oblong-lanceolate or wider, to 15 cm long. The stipules are brownish and 3-6 cm long. There are a few lanceolate stem leaves, reduced in size upwards on the stem.

The inflorescence is a terminal raceme, spike-like, from 3-6 cm longand 1-2 cm wide. It is densely white-flowered as seen in the photo above.


Habitat:

American bistort is a montane species found in moist or swampy meadows, streambanks, or alpine slopes.


Range:

American bistort is found from southern Alaska to southern California, east to Alberta, Montana, and New Mexico.


Leaf of American Bistort, Snakeweed, Mountain Meadow Knotweed, Western Bistort: Bistorta bistortoides (Synonyms: Persicaria bistortoides, Polygonum bistortoides, Polygonum bistortoides var. linearifolium, Polygonum bistortoides var. oblongifolium, Polygonum cephalophorum, Polygonum glastifolium, Polygonum vulcanicum)
The photo above shows a sessile stem leaf of american bistort.

Basal leaf of American Bistort, Snakeweed, Mountain Meadow Knotweed, Western Bistort: Bistorta bistortoides (Synonyms: Persicaria bistortoides, Polygonum bistortoides, Polygonum bistortoides var. linearifolium, Polygonum bistortoides var. oblongifolium, Polygonum cephalophorum, Polygonum glastifolium, Polygonum vulcanicum)

The photo above shows a petiolate basal leaf of americn bistort as seen along the Yakima-Klickitat county line.........May 29, 2006.

Inflorescence of American Bistort, Snakeweed, Mountain Meadow Knotweed, Western Bistort: Bistorta bistortoides (Synonyms: Persicaria bistortoides, Polygonum bistortoides, Polygonum bistortoides var. linearifolium, Polygonum bistortoides var. oblongifolium, Polygonum cephalophorum, Polygonum glastifolium, Polygonum vulcanicum)


Paul Slichter