Bohemian Knotweed - Polygonum x bohemicum
Fallopia x bohemica, Polygonum cuspidatum × Polygonum sachalinense
State Rank Reason (see State Rank above)
Part of the Japanese Knotweed Complex
- Details on Status Ranking and Review
Bohemian Knotweed (Polygonum x bohemicum) Conservation Status Review
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Glabrous to pubescent and often rhizomatous annual or perennial herb. Stems scandent to erect or less frequently prostrate. Ochrea chartaceous, sometimes deciduous. Petiole base articulated, extrafloral nectaries sometimes present. Leaves broadly ovate to triangular, margins entire or wavy. Inflorescences terminal and lateral, racemose to paniculate. Flowers bisexual, some plants bisexual or others only pistallate, 1-5 per ochreate fascicle. Tepals 5, petaloid, connate basally to nearly completely, dimorphic, the outer 3 winged or keeled and larger than inner 2. Stamens 6-8, anthers yellow to pink or red, ovate to elliptic. Styles 3, spreading, more or less connate below. Stigmas capitate, fimbriate or peltate. Achenes brown to dark brown or black, trigonous but not winged, glabrous (adapted from: Freeman & Hinds, 2005, in Flora N. America, Vol. 5).
Sporadically across North America; most widespread in WA and ID where it is a noxious weed. The MT report is from Mineral County (Kartesz in prep. 2012).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Disturbed places; in North America apparently reproducing mostly vegetatively by rhizomes (adapted from: Freeman & Hinds, 2005, in Flora N. America).
- Additional ReferencesLegend: View Online Publication
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- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.