Persicaria lapathifolia

willow weed

Family:Polygonaceae

Rarity

CNPS-EB: B

8 current natural populations

Criteria:

Limited/Threatened Habitat
Declining

Observations

CNPS-EB Database ⓘ
Calflora (group) ⓘ
Calflora (public)
iNaturalist
- Genus Persicaria
- Persicaria lapathifolia
CCH2

Key

Ecology

Flowers June - October

Habitats:

Miscellaneous Wetlands

All Persicaria

P. hydropiperoides (B)
P. lapathifolia
P. punctata (C)

References

Synonyms

Polygonum lapathifolium
Polygonum lapathifolium var. salicifolium
Polygonum scabrum

Populations

Key

Location	Pop ID	Last Recorded	Notes
Big Break, Antioch	19	2022-09-22
Concord Naval Weapons Station	9	2008-12-31
Contra Loma Rgnl Park	10	2005-08-15
Dublin, E of 680, N of 580	18	2019-12-31
Garin Rgnl Park	11	2020-10-23
Livermore - other or unknown sites	13	2023-11-14
San Pablo Reservoir - EBMUD	17	2023-08-23
Sunol Rgnl Wilderness	20	2025-08-18
Albany Hill	1	1999-10-31	Historic
Alvarado	2	1897-12-31	Historic
Antioch Dunes	3	1986-12-31	Historic
Antioch Shoreline	4	2000-10-01	Historic
Berkeley, West	6	1906-12-31	Historic
Bethel Island	7	1998-12-31	Historic
Byron Hot Springs area	8	1994-12-31	Historic
Los Vaqueros Watershed	12	1988-12-31	Historic
Niles Canyon area	14	1970-12-31	Historic
Oakland - other or unknown sites	15	1868-12-31	Historic
Oakland Shoreline	16	1958-12-31	Historic
UC Campus, Berkeley	5	1907-12-31	Historic

The list of populations shows the distinct populations identified by the CNPS-EB Rare and Unusual Plants Committee. The locations in this list are very general. More specific location details can be obtained from the links in the Observations section (for some of these links, a login is required).

Font

Populations in bold type have precise coordinates available for field volunteers and researchers.

Populations in normal type are only known from a description of the location; no precise coordinates are available.

Background

Populations with a white background have been observed in the last 25 years.

Populations with a blue background have not been observed for at least 25 years.

Populations with an orange background have an uncertain location or identification, or are planted.

Columns

Pop ID is a label that identifies the population. Many locations have more than one population of a species, and the population ID is used to distinguish them.