Camissonia benitensis

Last updated

Camissonia benitensis
Camissonia benitensis.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Myrtales
Family: Onagraceae
Genus: Camissonia
Species:
C. benitensis
Binomial name
Camissonia benitensis

Camissonia benitensis is a species of evening primrose known by the common names San Benito suncup [1] and San Benito evening primrose. It is endemic to the Diablo Range of the South Coast Ranges of California, where its range includes far southern San Benito County, far western Fresno County, and far eastern Monterey County.

Contents

The species is categorized as a strict serpentine endemic, meaning that it is almost always found growing on serpentine soils; however, at least 10 populations of the species are known to occur on greywacke substrates. Most of the habitat of the species is associated with the New Idria Serpentine Mass, Laguna Mountain Serpentine Mass, Hepsedam Peak Serpentine Mass, Panther Peak Serpentine Mass, Mustang Ridge Serpentine Mass, and numerous smaller serpentine masses between. These masses are surrounded by non-serpentine rocks of the Franciscan Formation, including greywacke which some populations of Camissonia benitensis occur. Serpentine is an ultramafic rock. It weathers to produce soils with characteristically low levels of nutrients like nitrogen, phosphorus, potassium, and calcium, and high levels of magnesium and heavy metals including nickel and chromium. A major, consistent chemical feature of serpentine soil is a bioavailable calcium:magnesium ratio much less than 1. Most nonserpentine soils have a ratio far greater than 1 (more calcium and much less magnesium). The extreme chemical characteristics of serpentine soils give rise to uniquely adapted and rare serpentine endemic plant species such as C. benitensis.

Like Camissonia benitensis, the previously ranked strict serpentine endemic Layia discoidea also has several populations that occur on greywacke and chert outcrops and talus around the New Idria Serpentine Mass. Additionally, the strict serpentine endemic Quercus durata var. durata also occurs on greywacke in the vicinity of Condon Peak adjacent to the New Idria Serpentine Mass. The occurrence of these strict serpentine endemics on graywacke suggests that greywacke has physical and or chemical characteristics similar to serpentine and may serve as a habitat analog.

Description

Camissonia benitensis was discovered by Peter H. Raven on a serpentine stream terrace adjacent to Clear Creek (New Idria serpentine mass; Bureau of Land Management Clear Creek Management Area) in 1960 and scientifically described by him in 1969. The plant's specific epithet, "benitensis", commemorates its discovery in San Benito County. It is a diminutive annual herb that rarely grows larger than 10 centimeters in field conditions, but can become multi-branched and exceed 30 centimeters in diameter within a horticultural setting. Its reddish stems bear plentiful linear leaves less than 1 centimeter long and minutely toothed along the edges. Plants bear four-petaled yellow flowers approximately 6 millimeters in diameter.

Camissonia benitensis seeds at and near the soil surface germinate with the first rains in fall or winter (November 1 - January 31). The plants grow through late fall, winter, and early spring (germination with first rainfall to April) and flowering in April and May. The species is fully self-pollinating. [2] [3] The fruit is a long, cylindrical capsule approximately 2 to 3 centimeters in length that matures May through July, becoming dry at full maturity with plant senescence. The fruits typically either do not open or only open part way near the tip and do not disperse most of the seed at maturity. It has been observed that most fruits fully open and seeds disperse with rain drop impact on the dry fruits - either during infrequent summer rain storms or with the first rains in fall. The seeds are about 1 millimeter long and 0.5 millimeter wide - the size of sand grains. They are black to brown in color and have a smooth seed coat. The seeds have a demonstrated longevity of at least 20 years in the soil seed bank. Long-distance seed dispersal likely occurs as seeds in mud stuck to animals or vehicles.

Camissonia benitensis bears a close resemblance to Camissonia contorta . [4] The two species are virtually indistinguishable with the naked eye when plants are small (under 6 centimeters), as is common in their native habitat, where they occur together. Camissonia strigulosa also grows in this range but is distinguishable by its smaller flowers and prostrate habit. They dichotomous keys in The Jepson Manual first edition are not detailed enough to make certain positive identifications. One key characteristic that can help distinguish the three species is the morphology of the trichomes on the distal inflorescences. C. contorta has trichomes that look like transparent glassy rods. C. strigulosa has white linear or lance-shaped blades. C. benitensis has both kinds of trichomes. This key characteristic was lacking in Jepson Manual first edition, but is now included in Jepson Manual second edition. [3]

A Camissonia which resembles either C. contorta or C. benitensis growing on serpentine soil in upland geologic transition zone habitat or serpentine stream terrace habitat within serpentine masses is virtually always C. benitensis. [3] A Camissonia resembling either of the two species on serpentine stream terraces outside of serpentine masses or mixed alluvium stream terraces could be either C. contorta or C. benitensis. [3] C. strigulosa is the common Camissonia species found growing on nonserpentine alluvial stream and river deposits within the range of C. benitensis.

Range and habitat

Based upon the original discovery of C. benitensis on a serpentine alluvial stream terrace adjacent to Clear Creek, it was long believed that its only habitat type consisted of serpentine alluvial terraces adjacent to perennial streams and rivers, a very rare type of habitat. Until 2010 few populations of the species had been found in any other habitat. In 2010 numerous additional populations were discovered on other land forms including ancient serpentine alluvium deposits (upland hills), serpentine landslides originating from tectonic masses (upland), and serpentine soils on the periphery of large tectonic serpentine (ultramafic) masses (upland)(USFWS 2020). These recently discovered habitat types are collectively called the "geologic transition zone." This habitat type is now known to constitute the majority of the habitat area and contains most of the known populations of the species (USFWS 2020). Populations found near Priest Valley in 2010 extended the previously known range 15 kilometers to the southeast (USFWS 2020).

Common features of the stream terrace are friable serpentine soils that are stable due to very low gradient or no slope and high percentage of coarser substrate particles including sand, gravel, and cobbles. The plant communities in the area include chaparral and woodland with gaps in between where there are microclimates. C. benitensis occurs in these gaps. Typical woody vegetation in the area includes Quercus douglasii (blue oak), Juniperus californica (California juniper), Quercus berberidifolia (scrub oak), Quercus durata (leather oak), Arctostaphylos glauca (bigberry manzanita) and Ceanothus cuneatus (buckbrush). Gaps between the woody vegetation have sparse herbaceous plant cover. C. benitensis is generally a poor competitor with other plant species, both native and exotic. Dense woody vegetation (closed shrub gaps) appears to be detrimental to C. benitensis due to shading effects. Some areas of geologic transition zone habitat have been partially invaded by invasive annual grasses such as Bromus madritensis . These infestations are usually sparse due to the extreme physical and chemical characteristics of the serpentine soils and the low level of tolerance of Bromus madritensis to those soil characteristics. Wildfire generally has a positive effect on C. benitensis by removing native and invasive vegetation. Prescribed fire is utilized by the Bureau of Land Management to control Centaurea solstitialis which once threatened to invade stream terrace habitat occupied by San Benito evening primrose near the confluence of Clear Creek and San Benito River. Some areas of geologic transition zone habitat on private land are grazed by cattle which like wildfire, is beneficial to C. benitensis by removing competing vegetation, particularly invasive annual grasses.

The current known range for Camissonia benitensis [5] is as follows:

Population dynamics

C. benitensis plant numbers fluctuate widely from year to year, up to two orders of magnitude, largely independently of total season rainfall and other climate factors including temperature. Cold winters have been documented to result in high seedling mortality due to the effects of soil frost heave (cyclical night freezing - day thawing) in the loose, sandy soil.

C. benitensis evening primrose is well-buffered from extinction by very large soil seed bank 100 - 1000 times that of the number of plants seen with a population in any given year (USFWS 2020). Seed in the soil seed bank has been documented by direct seed longevity test to be viable for at least 20 years and indirectly determined by inferred burial duration (under leaf litter of shrubs) to be viable for up to 105 years. Members of Onagraceae are well-known to have very large, long-lived soil seed banks.

Conservation

The town of New Idria was founded in 1848 with the discovery of cinnabar (mercury ore) within the New Idria serpentine mass (BLM Clear Creek Management Area). Numerous European prospectors and cattle ranchers settled throughout the area thereafter. Historic impacts to San Benito evening primrose have included logging and mining (gravel, magnesite, chromite, cinnabar, and chrysotile asbestos). The relatively level stream terraces were historically favored by settlers for home sites and to stage industrial activities. A proposed mineral withdrawal for the New Idria serpentine mass will greatly limit any future mining in the area.

In more recent decades, the BLM Clear Creek Management Area became a popular motorized off-road vehicle (ORV) recreation area. C. benitensis was federally listed as Threatened in 1985. [4] The primary threat cited by the Fish and Wildlife Service was off-road vehicle impacts to habitat. At the time, only nine populations of the species were known with most occurring on serpentine alluvial stream terraces within one of the highest ORV use areas at Clear Creek Management Area, Clear Creek Canyon. [4] Nearly all of the stream terrace habitat in Clear Creek Canyon has since been fenced to exclude human impacts. A formal route designation in 2005 has further reduced ORV impacts. [2]

The Clear Creek Management Area was under a temporary Emergency Closure instituted on May 1, 2008 [2] when the Environmental Protection Agency reported that natural occurrences of chrysotile asbestos in the soil was above safe limits for people. Clear Creek Management Area reopened to the public on March 14, 2014 with entry by permit only. Vehicle travel is open only to highway-licensed vehicles on the public touring route that includes Clear Creek Road (R1), Spanish Lake Road (R11), KCAC Road (R5), Sawmill Creek Road - south segment (T158), and San Benito Mountain Peak Road (R13). The main entry points on R1 (at Jade Mill Campground) and R11 (Idria Reservoir) are gated. Individuals may acquire an entry permit for up to 5 days of entry per year. The remainder of the routes formally designated in 2005 remain closed.

Synopsis

Discovery of the geologic transition zone habitat and numerous additional populations has greatly improved the outlook for C. benitensis. Most of the geologic transition zone habitat has not been subject to high levels of human impacts, unlike much of the stream terrace habitat. There are more than 600 known populations of C. benitensis. Only 10 populations were known when the species was federally listed in 1985. 60 populations were known by 2009 with most being within alluvial terrace habitat. 600 populations have since been found since 2010 with most of those being within the newly discovered geologic transition zone habitat. The known range is now several times larger than when the species was Federally listed. Most of the potential geologic transition habitat on both public (BLM and State land) and private land has now been surveyed.

A Federal Register notice from the US Fish and Wildlife Service published on June 1, 2020, proposed to remove Camissonia benitensis from the Federal List of Endangered and Threatened Plants. [6] A final Federal Register notice from the US Fish and Wildlife Service removing the species from the Federal List of Endangered and Threatened Plants was published on February 3, 2022, with an effective date of March 7, 2022. [7]

Related Research Articles

<span class="mw-page-title-main">San Benito County, California</span> County in California, United States

San Benito County, officially the County of San Benito, is a county located in the Coast Range Mountains of the U.S. state of California. As of the 2020 census, the population was 64,209. The county seat is Hollister.

<i>Euproserpinus euterpe</i> Species of moth

Euproserpinus euterpe, the Kern primrose sphinx moth or euterpe sphinx moth is a small day-flying moth in the family Sphingidae. The 0.04-inch (1.0 mm), light green eggs are laid haphazardly on various plants in the vicinity of the evening primrose host plants. Larvae emerge from the eggs about a week after oviposition and begin to feed on the flowers and young leaves of the evening primrose. Larvae hatching from eggs laid on other plants are able to wander significant distances to find the host plant.

<span class="mw-page-title-main">Diablo Range</span> Mountain range in the California Coastal Ranges

The Diablo Range is a mountain range in the California Coast Ranges subdivision of the Pacific Coast Ranges in northern California, United States. It stretches from the eastern San Francisco Bay Area at its northern end to the Salinas Valley area at its southern end.

<i>Camissonia</i> Genus of flowering plants

Camissonia, sometimes commonly known as sun cup or sundrop, is a genus of annual and perennial plants in the evening primrose family Onagraceae. A total of 12 species are known, nearly all from western North America, especially in the California Floristic Province, but also one from South America. Previous circumscriptions of the genus had recognized up to 62 species before it was split among other closely related genera.

<i>Calochortus tiburonensis</i> Species of flowering plant

Calochortus tiburonensis, the Tiburon Mariposa lily, is a rare member of the genus Calochortus in the family Liliaceae. It is endemic to Marin County, California, where it is known only from one population on Ring Mountain east of Mill Valley. There it occurs on a single serpentine outcrop in grasslands from 50–150 metres (160–490 ft) in elevation.

<span class="mw-page-title-main">San Benito Mountain</span>

San Benito Mountain is the highest mountain in the Diablo Range of California. The summit is at an elevation of 5,267 feet (1,605 m). The rock is composed of asbestos (chrysotile), an ultramafic rock. It weathers to produce serpentine soils with characteristically low levels of nutrients like nitrogen, phosphorus, potassium, and calcium, and high levels of magnesium and heavy metals including nickel and chromium. This means little vegetation grows in the area though there are some plants that only grow on such soils like the local endemic San Benito evening primrose. The Clear Creek Management Area includes the San Benito Mountain Research Natural Area, recognized for its unique pine and incense cedar forest assemblage. The Mediterranean climate is punctuated by cool, wet winters and hot, dry summers.

<i>Layia discoidea</i> Species of flowering plant

Layia discoidea is a rare species of flowering plant in the family Asteraceae known by the common name rayless tidytips, or rayless layia.

<i>Brodiaea pallida</i> Species of flowering plant

Brodiaea pallida is a rare species of flowering plant in the cluster-lily genus known by the common name Chinese Camp brodiaea.

<i>Calystegia stebbinsii</i> Species of morning glory

Calystegia stebbinsii is a rare species of morning glory known by the common name Stebbins' false bindweed. It is endemic to the Sierra Nevada foothills of California, where it is known from only two spots in El Dorado and Nevada Counties. It grows in unique habitat in chaparral on gabbro soils. It is a federally listed endangered species.

<i>Camissonia contorta</i> Species of flowering plant

Camissonia contorta is a species of evening primrose known by the common name plains evening primrose. It is an annual herb producing a slender, bending to curling red or green stem which is sometimes hairy. It is up to 30 centimeters long and erect or spreading out. The blue-green leaves are linear to very narrowly oval in shape and up to 3.5 centimeters long. The nodding inflorescence produces one or more small flowers. Each has bright yellow petals up to half a centimeter long, sometimes with small red dots near the bases. The fruit is a capsule about 3 centimeters long, containing 50 -100 tiny seeds.

<i>Ceanothus ferrisiae</i> Species of flowering plant

Ceanothus ferrisiae is a rare species of shrub in the family Rhamnaceae. Its common name is coyote ceanothus.

<span class="mw-page-title-main">Mono Hot Springs</span>

Mono Hot Springs is a summer resort and campground at a group of hot springs in Fresno County, central California. It is located within the Sierra National Forest, 70 miles (110 km) northeast of Fresno via California State Route 168.

<span class="mw-page-title-main">Pine Hill Ecological Reserve</span> California nature reserve

Pine Hill Ecological Reserve is a nature reserve of 403 acres (1.63 km2) located due east of Folsom Lake in the Sierra Nevada foothills, in El Dorado County, California. The reserve was established in 1979, and is managed by the Bureau of Land Management.

Solidago guiradonis is an uncommon species of goldenrod known by the common name Guirado goldenrod. It is native to the Central California Coast Ranges of central California, in southern San Benito and western Fresno Counties.

Trichostema rubisepalum is a species of flowering plant in the mint family known by the common name Hernandez's bluecurls.

<i>Zeltnera namatophila</i> Species of flowering plant

Zeltnera namatophila, the spring-loving centaury, is a rare species of flowering plant in the gentian family. It is endemic to the Amargosa Valley, in Nye County, southwestern Nevada.

<i>Gesneria pauciflora</i> Species of flowering plant

Gesneria pauciflora is a rare species of flowering plant in the family Gesneriaceae known by the common name yerba maricao de cueva. It is endemic to Puerto Rico, where there are only three populations remaining. It was federally listed as a threatened species of the United States in 1995.

<i>Thlaspi californicum</i> Species of flowering plant

Thlaspi californicum is a rare species of flowering plant in the family Brassicaceae known by the common name Kneeland Prairie penny-cress. It is endemic to California, where it is known from only one stretch of grassland in Humboldt County. It is threatened by development. It is a federally listed endangered species of the United States.

<span class="mw-page-title-main">Bay checkerspot butterfly</span> Subspecies of butterfly

The Bay checkerspot is a butterfly endemic to the San Francisco Bay region of the U.S. state of California. It is a federally threatened species, as a subspecies of Euphydryas editha.

<span class="mw-page-title-main">New Idria Mercury Mine</span> Quicksilver Mine in California, United States

The New Idria Mercury Mine encompasses 8,000 acres of land in the Diablo Mountain range, incorporating the town of Idria in San Benito County, California. Idria, initially named New Idria, is situated at 36°25′01″N120°40′24″W and 2440 feet (680m) above mean sea level. The area was, in the past, recorded in the US Census Bureau as a rural community; however, Idria has become a ghost town since the closing of once lucrative mining operations in the early 1970s.

References

  1. ↑ USDA, NRCS (n.d.). "Camissonia benitensis". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 2 May 2016.
  2. 1 2 3 USFWS. Camissonia benitensis Five-year Review. August 2009.
  3. 1 2 3 4 Taylor, D. W. (1990). Ecology and life history of the San Benito evening primrose. Bureau of Land Management, California State Office.
  4. 1 2 3 USFWS. Determination of threatened status for Camissonia benitensis. Federal Register February 12, 1985.
  5. ↑ "Observation Search - Calflora".
  6. ↑ "Federal Register :: Request Access".
  7. ↑ "Federal Register :: Request Access".
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.