Species Details

Polygonum polygaloides ssp. esotericum

Modoc County knotweed

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Photo of Polygonum polygaloides ssp. esotericum
©2013 Jake Ruygt
Scientific Name:
Polygonum polygaloides Meisn. ssp. esotericum (Wheeler) Hickman
Common Name:
Modoc County knotweed
Family: Polygonaceae
Element Code: PDPGN0L1Y2
USDA Plants Symbol: POPOE
Synonyms/Other Names:
CA Rare Plant Rank: 1B.3
Fed List: None
State List: None
Global Rank: G4G5T3
State Rank:
Other Status: BLM_S
CRPR Changes:
changed from 1B.1 to 1B.3 on 2017-12-13
Add Date: 1974-01-01
Date Edited: 2022-06-08
Lifeform: annual herb
Blooming Period: May-Sep
885 - 1690 meters
2905 - 5545 feet
General Habitat:
  • Great Basin scrub
  • Lower montane coniferous forest
  • Meadows and seeps
  • Vernal pools
General Micro Habitat:
Micro Habitat:
  • Mesic
Possibly threatened by grazing, trampling, road maintenance, and non-native plants. Intermediates to ssp. confertiflorum are common, especially on Modoc Plateau to OR. Difficult to distinguish pure stands of ssp. esotericum in CA; needs further study. Only occurrences that mostly contain P. p. ssp. esotericum are included. See Rhodora 40(476):310-312 (1938) for original description, and MadroƱo 31(4):251 (1984) for revised nomenclature.
Total Occurrences: 45
Element Occurrence Ranks:
5 10 2 0 0 28
Occurrence Status:
Historical >20 Years 40
Recent <=20 Years 5
Presumed Extant 45
Possibly Extirpated 0
Presumed Extirpated 0
California Endemic:
California Island:
States: Name (Code)
California (CA), Oregon (OR)
California Counties and Islands: Name (Code)
Modoc (MOD), Plumas (PLU), Shasta (SHA), Sierra (SIE)
Quads: Name (Quad Code)
Barrel Springs (4111988), Crooks Meadow (4111978), Ambrose (4112058), Antelope Valley (3912063), Beaver Mtn. (4112086), Boles Meadows East (4112067), Boles Meadows West (4112068), Burney Falls (4112116), Calpine (3912064), Crank Mountain (4112142), Davis Creek (4112063), Jacks Butte (4112057), Knobcone Butte (4112151), Lake Annie (4112081), Larkspur Hills (4112071), Lookout (4112122), McGinty Reservoir (4112075), Mt. Bidwell (4112082), Pease Flat (4112085), Reconnaissance Peak (3912073), Rimrock Lake (4112162), South Mtn. (4112076), Spaulding Butte (4112152), Washington Mtn. (4112048), Whitehorse (4112134), Whittemore Ridge (4112066)
Definitions of codes following a county and/or quad:
* Presumed extirpated
(?) Occurrence confirmed, but possibly extirpated
Quad and county data is imported from the CNDDB. Species may be present in other areas where conditions are favorable. These data should NOT be substituted for pre-project review or for on-site surveys.


Presumed Extant
Counties   Quads