Taxon Report

Lilaeopsis masonii Math. & Const.

Mason's lilaeopsis

Print Report


Taxon Summary

Lilaeopsis masonii, commonly known as Mason's lilaeopsis, is a perennial rhizomatous herb in the Apiaceae that is found only in California. It occurs within Marshes and swamps (brackish, freshwater), and Riparian scrub, growing at elevations from 0 to 10 meters. Lilaeopsis masonii is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

  Classification
Scientific Name:
 Lilaeopsis masonii Math. & Const.
Common Name:
 Mason's lilaeopsis
Family: Apiaceae
Element Code: PDAPI19030
USDA Plants Symbol: LIMA7
Synonyms/Other Names:

Ecology and Life History
Lifeform: perennial rhizomatous herb
Blooming Period: Apr-Nov Apr-Nov
Elevation: 0-10 (0-35)
General Habitats: Marshes and swamps, Riparian scrub
Microhabitat:
Microhabitat Details:

Conservation Status
CA Rare Plant Rank: 1B.1
Global Rank: G2
State Rank:
 S2
State List: CR
Fed List: None
Other Status:
CRPR Changes:

Occurrence Data from the CNDDB
Total Occurrences: 209
Element Occurrence Ranks:
   Excellent (A) 8
   Good (B) 97
   Fair (C) 37
   Poor (D) 9
   None (X) 1
   Unknown (U) 57

Location
California Endemic:  True
California Counties and Islands: Name (Code)
Alameda (ALA), Contra Costa (CCA), Marin (MRN), Napa (NAP), Sacramento (SAC), San Joaquin (SJQ), Solano (SOL), Yolo (YOL)
Quads: Name (Quad Code)
Antioch North (3812117), Benicia (3812212), Bouldin Island (3812115), Bruceville (3812134), Clarksburg (3812145), Clifton Court Forebay (3712175), Cuttings Wharf (3812223), Denverton (3812128), Dozier (3812137), Fairfield South (3812221), Holt (3712184), Honker Bay (3812118), Inverness (3812217), Isleton (3812125), Jersey Island (3812116), Liberty Island (3812136), Lodi South (3812113), Mare Island (3812213), Napa (3812233), Rio Vista (3812126), Saxon (3812146), Terminous (3812114), Thornton (3812124), Union Island (3712174), Vine Hill (3812211), Woodward Island (3712185)

Threat List Data from the CNDDB

Threat List Total: 13
EOs with Threat Listed: Total EOs % of EOs
102 49 %
Erosion/runoff 56 26%
Waterway bank protection/maintenance 33 15%
Recreational use (non-ORV) 32 15%
Other 19 9%
Non-native plant impacts 16 7%
Foot traffic/trampling 15 7%
Vandalism/dumping/litter 9 4%
Altered flood/tidal/hydrologic regime 8 3%
Development 4 1%
Grazing 3 1%
Biocides 2 0%
Pollution 2 0%
Surface water diversion 2 0%

Notes
Locally common in Suisun Bay. Threatened by erosion, channel stabilization, development, flood control projects, recreation, agriculture, shading resulting from marsh succession, and competition with non-native Eichhornia crassipes. Many populations ephemeral, exploiting newly deposited or exposed sediments. Collection from Chicken Ranch Beach, MRN Co. (485D) is probably L. occidentalis. Treated differently here than Madroño 58(3):131-144 (2011), which treats L. masonii as a synonym of L. occidentalis. See Madroño 24(2):81 (1977) for original description.
Threats:
Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 10 February 2025].