Beach Layia (Layia carnosa)

The sunflower family (Asteraceae, also known as Compositae) is the largest family of dicots, consisting of some 1,300 genera and 21,000 species worldwide. It is also the largest plant family in California. The Jepson Manual lists 710 native species and 155 naturalized species in 205 genera found in the state. Of the 39 taxa listed in our chapter’s publication Rare and Endangered Plants of San Francisco’s Wild and Scenic Places (revised January 2000), ten (26%) are members of the Asteraceae. Of the 1,742 taxa listed in the CNPS Inventory of Rare and Endangered Vascular Plants of California, 222 (12.7%) belong to the Asteraceae.

The genus Layia is a member of the Heliantheae tribe (subtribe Madiinae). The subtribe includes such common Bay Area genera as Achyrachaena (blow-wives), and Lagophylla, Madia, Hemizonia, Holocarpha, and Blepharizonia (all tarplants and tarweeds). Layias are low annuals with white to yellow ray flowers and yellow disk flowers. Perhaps the most familiar member of the genus is tidy tips (Layia platyglossa), a prominent player in some of California’s most impressive wildflower fields.

Beach LayiaBeach layia is a prostrate herb inhabiting coastal strand and coastal dune habitats from sea level to 60 feet in elevation. It has been recorded from as far south as Point Conception and as far north as Humboldt County. Although plenty of suitable habitat is available in southern Oregon, to my knowledge the species has not been recorded there. Specifically, it is extant in Humboldt County (Humboldt Bay dunes), Santa Barbara County (Vandenburg Air Force Base), Monterey County (Del Monte Forest) and Marin County (Point Reyes Peninsula). Beach layia is protected in part at two locations owned and managed by the Bureau of Land Management; these include the Manila Dunes Area of Critical Environmental Concern (ACEC) and the Mattole Beach ACEC.

Although the California Native Plant Society’s Inventory of Rare and Endangered Vascular Plants of California indicates that beach layia is presumed extirpated from San Francisco County, the species was not recorded in Howell, Raven, and Rubtzoff’s 1958 A Flora of San Francisco, California. However, abundant suitable habitat was present in the Sunset District prior to development, so that the species occurrence there is easy to imagine, and its presence in San Francisco is specifically referred to by John Hunter Thomas in his 1961 Flora of the Santa Cruz Mountains of California.

Beach layia is glandular but unscented, prostrate to erect, from one to seven inches high. It produces four to ten white ray flowers (ligules) and five to 45 yellow disk flowers from March to July. It is distinguished from other layias by the presence of plumose non-woolly pappus, glandular herbage, and purple anthers.

Like so many other inhabitants of coastal strand and dune communities, beach layia has suffered mightily at the hands of humans. This already dynamic habitat has been seriously degraded by off-highway vehicle use, hikers, and, more recently, invasive exotic plants. Lands that were once shunned as wastelands due to the ever-shifting sands have become increasingly valuable for their proximity to the ocean, fresh air, and views. Some of San Francisco’s other dune inhabitants that have been eliminated or threatened with extirpation include San Francisco lessingia (Lessingia germanorum), San Francisco Bay spineflower (Chorizanthe cuspidata var. cuspidata), compact cobweb thistle (Cirsium occidentale var. compactum), round-headed Chinese houses (Collinsia corymbosa), San Francisco wallflower (Erysimum franciscanum), dune gilia (Gilia capitata ssp. chamissonis), many-stemmed gilia (G. millefoliata), wedge-leaved horkelia (Horkelia cuneata ssp. sericea), large-flowered linanthus (Linanthus grandiflorus), curly-leaved monardella (Monardella undulata), and San Francisco campion (Silene verecunda ssp. verecunda), among others.

Beach layia was listed as endangered by the State of California in January 1990. The federal government listed it as endangered in June 1992. It is also on the CNPS’ List 1B 3-3-3, the highest level on endangerment short of extinction (highly restricted occurrence, endangered throughout its range, and endemic to California). As such, any impacts to the species must be considered as significantly adverse pursuant to the California Environmental Quality Act, and appropriate mitigation measures must be developed to reduce impacts to a level that is less than significant. Typically, mitigation measures are developed in consultation with the U.S. Fish and Wildlife Service and the California Department of Fish and Game.