''Pentachaeta lyonii'', the Lyon's pentachaeta or Lyon's pygmydaisy, is an annual plant in the family

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to southern

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, where it is now known only from a few areas on the heavily developed coastline of

Los Angeles Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...

and Ventura counties. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

Distribution

At one point in time there were 43 populations of ''P. lyonii'' distributed among the

Santa Monica Mountains The Santa Monica Mountains are a coastal mountain range in Southern California, next to the Pacific Ocean. It is part of the Transverse Ranges. The Santa Monica Mountains National Recreation Area encompasses this mountain range. Because of its p ...

Simi Valley Simi Valley (; Chumash: ''Shimiyi'') is a city in the valley of the same name in southeastern Ventura County, California, United States. It is from Downtown Los Angeles, making it part of the Greater Los Angeles Area. Simi Valley borders Th ...

Palos Verdes Peninsula The Palos Verdes Peninsula () is a peninsular subregion of the Los Angeles metropolitan area, located within southwestern Los Angeles County, California. It is often called simply "Palos Verdes", and is made up of a group of cities in the Palos ...

and Catalina Island. In a 2006 search only 21 ''Pentacheata'' populations could be located, with occurrences on the Palos Verdes Peninsula having long been deemed

extirpated Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a chan ...

. Populations on Catalina Island were thought to be extirpated until 112 individuals were re-discovered in 2011 on a ridgeline near Two Harbors. The most recent area suspected of extirpation is Stunt Ranch where no flowering individuals have been seen since 1990, after an 8-year population decline.U.S. Fish and Wildlife Service. 1999. Recovery Plan for Six Plants from the Mountains Surrounding the Los Angeles Basin. In 2020 this elusive species was spotted once again by Catalina Island Conservancy botanists. Just 19 individuals were found in a location that roughly corresponds to a record from W.S. Lyon, who discovered the species in 1885. The plant received protected status in 1990.

Description

''Pentachaeta lyonii'' tends to grow in compact soil with little disturbance and few competitors. Plants have been grown in the greenhouse with light well aerated soil, but whether ''P. lyonii'' grows in compact soil due to a lack of competition or particular nutrient requirements has yet to be determined. The plant requires insect pollination to set seed.

References

External links

Calflora Database: ''Pentachaeta lyonii'' (Lyon's pentachaeta, Lyon's pygmydaisy)Jepson Manual eFlora treatment of ''Pentachaeta lyonii''USDA Plants Profile for ''Pentachaeta lyonii''UC CalPhotos gallery of ''Pentachaeta lyonii''
Astereae Endemic flora of California Natural history of the California chaparral and woodlands Natural history of the Santa Monica Mountains Natural history of Los Angeles County, California Natural history of Ventura County, California Taxa named by Asa Gray {{Astereae-stub