Limnanthes vinculans, the Sebastopol meadowfoam, is an endangered species of meadowfoam found only in the Laguna de Santa Rosa in Sonoma County, California, United States and an area slightly to the south in the Americano Creek and Washoe Creek watersheds. The name vinculans derives from the Latin root vinculum, meaning "a bond, a cord." The specific epithet vinculans means linking or bonding, in reference to the sharing of some characters of L. vinculans with L. douglasii (R.Br) and L. bakeri.
Platanthera yadonii, also known as Yadon's piperia or Yadon's rein orchid, is an endangered orchid endemic to a narrow range of coastal habitat in northern Monterey County, California. In 1998 this plant was designated as an endangered species by the United States government, the major threat to its survival being continuing land development from an expanding human population and associated habitat loss. One of the habitats of Yadon's piperia, the Del Monte Forest near Monterey, California, is the subject of a federal lawsuit, based upon endangerment of this organism along with several other endangered species.
Acanthomintha duttonii is a species of annual plant endemic to San Mateo County, California in the family Lamiaceae. It is commonly called San Mateo thornmint and is found growing on serpentine soils near the Crystal Springs Reservoir in a six-mile (10 km) long strip on the east side of Montara Mountain at elevations of approximately 150 to 300 meters.
Chorizanthe blakleyi is a rare species of flowering plant in the buckwheat family known by the common name Blakley's spineflower. It is endemic to the Sierra Madre Mountains of Santa Barbara County, California, where it is known from only eight occurrences, four of which are within the bounds of the Los Padres National Forest. It grows only on north-facing slopes in chaparral and woodland habitat. This plant grows upright to no more than 15 centimeters tall. It is yellow-green and hairy, with a few basal leaves up to about 2 centimeters long. The inflorescence contains several flowers, each surrounded by a tube of six hairy bracts with straight or hooked awns. The flower is a few millimeters wide with white or pink deeply notched tepals.
Chorizanthe rectispina is a species of flowering plant in the buckwheat family known by the common names prickly spineflower and straight-awned spineflower. It is endemic to California, where it is known from about twenty occurrences from Monterey to Santa Barbara Counties. It grows in dry habitat types such as chaparral and woodland in the hills of the Central Coast Ranges. It is a low, spreading plant with stems up to about 25 centimeters long, grayish to greenish in color and hairy in texture. The inflorescence is a cluster of flowers, each flower surrounded by six hairy bracts which are grayish to pink in color and tipped with awns. One bract is longer than the others and has a straight awn, and the other smaller bracts may have hooked awns. The tiny flower at the center of the bract array is a few millimeters wide and white and yellow in color.
Maculigilia maculatus is a species of flowering plant in the phlox family. It is known by the common names San Bernardino Mountain gilia and Little San Bernardino Mountains gilia. It is the sole species in genus Maculigilia. It is endemic to California, where it is known only from a few locales in the Little San Bernardino Mountains and the adjacent Palm Springs area in the northern end of the Coachella Valley. The largest populations, which may contain thousands of individuals, are located within the bounds of Joshua Tree National Park.
Acmispon rubriflorus, synonym Lotus rubriflorus, is a species of legume endemic to California. It is known by the common name red-flowered bird's-foot trefoil. It is known from only four occurrences with a disjunct distribution.
Harmonia stebbinsii is a species of flowering plant in the family Asteraceae known by the common name Stebbins' tarweed, or Stebbins' madia. It is endemic to northern California, where it is limited to the Klamath Mountains and adjacent slopes of the North Coast Ranges. It is a member of the serpentine soils plant community in these mountains, found at elevations of 1100–1600 meters. It is a rare annual herb producing a bristly stem up to about 25 centimeters tall studded with black resin glands. Its bristly leaves grow up to about 2 centimeters long and are mostly gathered near the base of the plant. The inflorescence is an array of flower heads lined with hairy, glandular, purple-tipped phyllaries. The head has a few yellow ray florets several millimeters long and yellow disc florets. The fruit is an achene tipped with a pappus.
Microseris bigelovii is a species of flowering plant in the family Asteraceae known by the common name coastal silverpuffs. It is native to the west coast of North America, where its range extends from the southern tip of Vancouver Island to the northern coast of California.
Sabulina decumbens is a rare species of flowering plant in the family Caryophyllaceae known by the common names The Lassics sandwort and Lassicus stitchwort.
Nitrophila mohavensis is a rare species of flowering plant in the family Amaranthaceae known by the common name Amargosa niterwort. It is endemic to Nye County in southwestern Nevada and Inyo County, in eastern California.
Oryctes is a genus of flowering plants in the nightshade family containing the single species Oryctes nevadensis, which is known by the common name Nevada oryctes. This rare plant is native to a small area of desert straddling the California - Nevada border, where it grows in habitat with deep sand. It is difficult to estimate its abundance because the plant is only seen in years with certain rainfall amounts and temperature ranges. This is a small annual herb growing from a taproot and producing sticky, scaly foliage, growing up to about 20 centimeters in maximum height. The leaves are 1 to 3 centimeters long, linear in shape to oval and divided into lobes, sometimes wavy along the edges. The inflorescences are umbels of a few tiny flowers each, emerging from leaf axils. The flower is purplish and rounded into an urn shape, measuring a few millimeters wide. The fruit is a spherical capsule containing several seeds. The plant typically flowers in the spring months of April, May and June.
Sedella leiocarpa is a rare species of flowering plant in the family Crassulaceae known by the common names Lake County mock stonecrop and Lake County stonecrop. It is endemic to Lake County, California, where it is known from only about ten occurrences in two locations. It is a resident of drying vernal pools and rocky clay flats, where it grows in colonies. It is a federally listed endangered species. This is an annual herb growing no more than four centimeters high. It is a tiny erect reddish or yellow succulent plant with sparse leaves each a few millimeters long. The flowers have yellow to reddish petals 3 or 4 millimeters long.
Penstemon barnebyi is a species of penstemon known by the common names White River Valley beardtongue and Barneby's beardtongue. It is native to the mountain and basin territory of central western Nevada, where it grows in sagebrush and woodland; there is also one occurrence just over the California border.
Pentachaeta exilis is a species of flowering plant in the family Asteraceae known by the common name meager pygmydaisy. It is endemic to California, where it is known from the North Coast Ranges to the southern Central Valley, San Joaquin Valley, and Sierra Nevada foothills. It is a member of grassland and woodland plant communities.
Pseudobahia bahiifolia is a rare species of flowering plant in the family Asteraceae known by the common name Hartweg's golden sunburst.
Baccharis malibuensis is a rare California species of shrubs in the family Asteraceae known by the common name Malibu baccharis.
Eriogonum evanidum is a rare species of wild buckwheat known by the common name vanishing wild buckwheat. It is native to southern California and Baja California, where it has been collected from widely scattered areas. Most historical occurrences are now extirpated. Some sources suggested that it was probably extinct, but living specimens were rediscovered in 2007.
Juncus digitatus is a rare species of rush known by the common name finger rush. It is endemic to Shasta County, California, where it is known from only two occurrences near Shingletown. It occurs in spring-moist habitat such as vernal pools in sunny locations in the foothills of the southernmost Cascade Range. The plant was first collected in 1991 and described to science as a new species in 2008.
Deinandra conjugens is a rare species of flowering plant in the family Asteraceae known by the common names Otay tarplant and Otay tarweed. It is native to a small section of far northern Baja California in Mexico, its range extending north into San Diego County, California, in the United States. One isolated population has been reported from the hills east of Cayucos in San Luis Obispo County.
