''Mucronea californica'' is a rare species of

annual plant An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical ...

in the family

Polygonaceae The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus ''Polygonum'', and was first used by Antoine Laurent de Jussieu in 1789 ...

known by the common names California spineflower or California mucronea. An ephemeral plant found growing in the sandy microhabitats of

coastal sage scrub Coastal sage scrub, also known as coastal scrub, CSS, or soft chaparral, is a low scrubland plant community of the California coastal sage and chaparral subecoregion, found in coastal California and northwestern coastal Baja California. It is w ...

chaparral Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranean c ...

and

dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...

s, this plant is threatened by the urbanization and development of its viable habitat and has been locally

extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

over much of its range. It has small, white to pink flowers that top

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

s spined with awns.

Description

An ephemeral

, this species grows narrow leaves from a rosette, and develops a spiny, awn-covered inflorescence with white to pink flowers on the top.

Morphology

This species grows by in diameter. The leaves form a basal rosette, attached to the plant via a petiole long. The leaves are shaped narrowly spatulate to obovate, measuring long by . The

is cyme-like. There are 3

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

s, which are spreading to nearly erect, and are connate for half of their length, shaped triangular to ovate or oblong. The bracts become acerose at the terminal nodes, and then linear to linear-lanceolate, long, with the apex acute to obtuse. The inflorescence is covered in awns, which are long. The involucres are 3-angled and obscurely ribbed, with 3 teeth. Their surface is glandular to slightly hirsute, with awns long. Flowering is from March to August. The singular flowers have a

perianth The perianth (perigonium, perigon or perigone in monocots) is the non-reproductive part of the flower, and structure that forms an envelope surrounding the sexual organs, consisting of the calyx (sepals) and the corolla (petals) or tepals when ...

large, pubescent near the base on the lower surface. The

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s are oblong, with an entire apex. There are 6 to 9 stamens. The fruits are

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

s .

Distribution and habitat

This species is endemic to

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, and is found mostly on the Pacific Coast ranging from

San Luis Obispo San Luis Obispo (; Spanish for " St. Louis the Bishop", ; Chumash: ''tiłhini'') is a city and county seat of San Luis Obispo County, in the U.S. state of California. Located on the Central Coast of California, San Luis Obispo is roughly halfwa ...

south to

San Diego County San Diego County (), officially the County of San Diego, is a county in the southwestern corner of the U.S. state of California. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the fi ...

, along with a number of locations inland from

Monterey County Monterey County ( ), officially the County of Monterey, is a county located on the Pacific coast in the U.S. state of California. As of the 2020 census, its population was 439,035. The county's largest city and county seat is Salinas. Montere ...

to western

Riverside County Riverside County is a county located in the southern portion of the U.S. state of California. As of the 2020 census, the population was 2,418,185, making it the fourth-most populous county in California and the 10th-most populous in the Unit ...

. It is found along sandy openings in a variety of habitats, from

communities, and dunes to sandy substrates in

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

s and pine-oak

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

s. It is threatened and in substantial decline from the extensive urbanization in

southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...

, which has made it locally extirpated over much of its historical range.

Gallery

File:Mucronea californica 38625082.jpg, Growing in habitat,

San Luis Obispo County San Luis Obispo County (), officially the County of San Luis Obispo, is a county on the Central Coast of California. As of the 2020 census, the population was 282,424. The county seat is San Luis Obispo. Junípero Serra founded the Mission ...

File:Mucronea californica 38625041.jpg, Growing in sand with developing inflorescences File:Mucronea californica 38623474.jpg, Note the spiny awns on the inflorescence File:Mucronea californica 71733385.jpg, Growing in habitat,

Morro Bay Morro Bay (''Morro'', Spanish for "Hill") is a seaside city in San Luis Obispo County, California. Located on the Central Coast of California, the city population was 10,757 as of the 2020 census, up from 10,234 at the 2010 census. The town ...

References

External links

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Gallery on CalPhotos

USDA Plants Profile
{{Taxonbar, from=Q15598817 Endemic flora of California Natural history of the California chaparral and woodlands Taxa named by George Bentham Plants described in 1836 Polygonaceae