Monterey Clover

(Trifolium trichocalyx)

Monterey clover is a California endangered plant species, which means that killing or possessing plants is prohibited by the California Endangered Species Act (CESA). The species is also listed as endangered under the federal link opens in new windowEndangered Species Act. Monterey clover is a small annual herb of the pea family (Fabaceae) with numerous flowers clustered into heads that are suspended by a whorl of specialized leaves, called laciniate-toothed involucres. Monterey clover is a “classic fire follower,” taking advantage of the high light exposure produced after a forest has been reduced by wildfire. There is evidence that the seed bank of this plant is capable of surviving more than 85 years.

At the time of this webpage posting, the California Natural Diversity Database reports six natural occurrences of this species that are presumed to still exist. The populations are clustered in two areas: one in Monterey County and the other near Point Arena in Mendocino County. However, because the species is a fire follower, the known distribution may be a product of recent fire history, and the actual distribution of the species in the soil seed bank may be different. 

The possibility of extinction may be high for this species, due to the small amount of known habitat and the ephemeral nature of the plant’s reappearance after fire. Monterey clover, though permanently protected by easements at most of its known locations, does not have room to expand due to residential and recreational developments nearby. Undeveloped lands in the plant’s vicinity that are unprotected are vulnerable to future development. Remaining habitat should be maintained and a natural fire regime should be established to support the species. Because the entire distribution is not well identified and limited data has been collected on the ecology of the species to date, further studies need to be conducted to better understand Monterey clover and identify other locations where it may occur.

CDFW may issue permits for Monterey clover pursuant to CESA, and you can learn more about the California laws protecting Monterey clover and other California native plants. Populations of Monterey clover occur in CDFW’s Northern Region and Central Region. More information is also available from the link opens in new windowU.S. Fish and Wildlife Service Species Profile for Monterey clover.

For more information on any of the topics above, please contact the Native Plant Program at

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Photo of Monterey clover flowers
Trifolium trichocalyx, Photo © Kerry Heise

Trifolium trichocalyx - CDFW Illustration by Mary Ann Showers
Trifolium trichocalyx, CDFW Illustration by Mary Ann Showers, click for full-sized image.