Taxon Report

Pentachaeta lyonii Gray

Lyon's pentachaeta

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Taxon Summary

Pentachaeta lyonii, commonly known as Lyon's pentachaeta, is a annual herb in the Asteraceae that is found only in California. It occurs within Chaparral (openings), Coastal scrub, and Valley and foothill grassland, growing at elevations from 30 to 690 meters. Pentachaeta lyonii is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.


  Classification

Scientific Name:
Pentachaeta lyonii Gray
Common Name:
Lyon's pentachaeta
Family: Asteraceae
Element Code: PDAST6X060
USDA Plants Symbol: PELY4
Synonyms/Other Names:

Ecology and Life History

Lifeform: annual herb
Blooming Period: (Feb)Mar-Aug (Feb)Mar-Aug
Elevation: 30-690 (100-2265)
General Habitats: Chaparral, Coastal scrub, Valley and foothill grassland
Microhabitat: Clay, Rocky
Microhabitat Details:

Occurrence Data from the CNDDB

Total Occurrences: 45
Element Occurrence Ranks:
   Excellent (A) 3
   Good (B) 19
   Fair (C) 10
   Poor (D) 3
   None (X) 6
   Unknown (U) 4
California Endemic:  True
California Counties and Islands: Name (Code)
Los Angeles (LAX), Ventura (VEN)
Quads: Name (Quad Code)
Long Beach (3311872)*, Malibu Beach (3411816), Newbury Park (3411828), Point Dume (3411817), San Pedro (3311863)*, Santa Catalina North (3311844)?*, Simi (3411837), Thousand Oaks (3411827), Torrance (3311873)

Threat List Data from the CNDDB

Threat List Total: 14
EOs with Threat Listed: Total EOs % of EOs
38 84 %
Development 25 55%
Non-native plant impacts 22 48%
Recreational use (non-ORV) 14 31%
Foot traffic/trampling 13 28%
Road/trail construction/maint. 10 22%
Other 10 22%
ORV activity 8 17%
Grazing 5 11%
Vandalism/dumping/litter 5 11%
Wood cutting or brush clearing 5 11%
Disking 4 8%
Non-native animal impacts 4 8%
Agriculture 1 2%
Improper burning regime 1 2%

Notes

Threatened by development, alteration of fire regimes, trampling, vehicles, and recreational activities. Seriously threatened by non-native plants; annual non-native grasses are an indirect factor contributing to extirpation. No successful translocation attempts as of 1994. See Synoptical Flora of North America 1(2):446 (1884) for original description, University of California Publications in Botany 65:1-41 (1973) for taxonomic treatment, and Madroño 58(2):69-77 (2011) for information on the impacts of non-native plants and management implications.
Threats:
Taxonomy:
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 29 March 2025].