Horkelia bolanderi is a rare species of flowering plant in the family Rosaceae. It is endemic to northern California where it is known from only a few occurrences in two or three counties. It grows in the mountain forests of the North Coast Ranges. This is a mat-forming gray-green perennial herb producing hairy erect stems 10 to 30 centimeters tall. The leaves are 3 to 8 centimeters long and are made up of hairy, toothed leaflets each one half to one centimeter long. The inflorescence holds several flowers, each with five white petals and up to 20 pistils in the center.
Arctostaphylos obispoensis is a species of manzanita, known by the common names bishop manzanita and serpentine manzanita, endemic to California.
Astragalus inversus is a species of milkvetch known by the common name Susanville milkvetch.
Astragalus jaegerianus is a rare species of milkvetch known by the common name Lane Mountain milkvetch. The plant was named for the biologist Edmund Jaeger, who first documented it in 1939.
Astragalus shevockii is a rare species of milkvetch known by the common names Little Kern milkvetch and Shevock's milkvetch. It is endemic to Tulare County, California, where it grows in the High Sierra, generally on granite-based soils in Jeffrey pine forests.
Hieracium argutum is a species of flowering plant in the aster family known by the common name southern hawkweed.
Lupinus padre-crowleyi is a rare species of lupine known by the common names DeDecker's lupine and Father Crowley's lupine. It is endemic to California, where it is known only from the eastern slopes of the Sierra Nevada and the high plateau below along the western border of Inyo County. It grows in the granite soils of the mountain forests and scrub. It has been noted at fewer than 20 locations. This is a perennial herb growing an erect inflorescence from a mat of silvery, woolly-haired herbage, reaching maximum heights over half a meter. Each palmate leaf is made up of 6 to 9 leaflets up to 7.5 centimeters long. The inflorescence is a raceme of whorled flowers each just over a centimeter long. The flower is cream to pale brownish yellow in color. The fruit is a silky-haired legume pod containing black-mottled white seeds.
Lupinus stiversii is a species of lupine known by the common names harlequin annual lupine and harlequin lupine. The plant was named for Army physician Dr. Charles Austin Stivers, who first collected it in 1862 near Yosemite.
Malacothamnus davidsonii, also known by the common names Davidson's bushmallow and Davidson's bush mallow, is a species of flowering plant in the mallow family.
Monardella cinerea is a rare species of flowering plant in the mint family known by the common name gray monardella. It is endemic to California, where it is known from the San Gabriel Mountains and San Jacinto Mountains in the Los Angeles area, and the central coast Santa Lucia Mountains in the Los Padres National Forest. It grows in rocky forested areas.
Oenothera wolfii is a rare species of flowering plant in the evening primrose family known by the common name Wolf's evening primrose. It is native to the coastline of southern Oregon and northern California, where it grows in coastal prairie, dunes, and coastal forest and woodland habitat. As of 1997 it was known from only about 16 occurrences. The biggest threat to the plant is its easy hybridization with its relative and probable descendant, Oenothera glazioviana. As this rare wild plant crosses with the introduced garden escapee, introgression occurs, causing what is known as genetic pollution; fewer pure individuals of O. wolfii will be seen as they are outnumbered by hybrids.
Phacelia brachyloba is a species of phacelia known by the common name shortlobe phacelia. It is native to southern California and Baja California, where it grows in the coastal mountains, canyons, and valleys. It is one of the many species known as fire followers, that emerge in areas recently burned.
Rhinotropis californica, synonym Polygala californica, is a species of flowering plant in the milkwort family known by the common name California milkwort. It is native to southwestern Oregon and northern and central California, where it grows in the coastal mountain ranges in local habitat types such as chaparral and forest. It is a perennial herb producing spreading stems, generally decumbent in form, up to about 35 centimeters in maximum length, lined with narrow oval leaves each a few centimeter long. The upper inflorescences produce several open flowers, and there may be some closed, cleistogamous flowers lower on the plant. The open flowers have pink or white winglike lateral sepals with hairy edges. The petals are similar in color, the central one tipped with a white or yellow beak. The fruit is a flattened green capsule up to a centimeter long containing hairy seeds.
Silene marmorensis is a rare species of flowering plant in the family Caryophyllaceae known by the common names Marble Mountain catchfly, Marble Mountain campion, and Somes Bar campion. It is endemic to the southern Klamath Mountains of northern California, where it grows in mountain woodlands and forests. It is a perennial herb producing several stems and shoots from a woody, branching caudex and thick taproot. The hairy, glandular stems grow erect to a maximum height near 40 centimeters. The lance-shaped leaves are a few centimeters long and are borne in pairs, the lowermost drying early. The inflorescence is a terminal cyme of flowers at the top of the stem, and some flowers may occur in the leaf axils. Each flower has a hairy, veined calyx of fused sepals. The flowers bloom at night, the five pinkish or green-tinged petals opening at the tip of the calyx.
Agnorhiza ovata is a species of flowering plant known by the common name southern mule's ears. It is native to the mountains and foothills of southern California and Baja California, occurring the Coast Ranges and Sierra Nevada foothills in Tulare, Kern, Ventura, Los Angeles, Orange, Riverside, and San Diego counties in California, with additional populations in the Peninsular Ranges south of the international border.
Baccharis malibuensis is a rare California species of shrubs in the family Asteraceae known by the common name Malibu baccharis.
Eriogonum spectabile is a rare species of wild buckwheat known by the common name Barron's buckwheat. It is endemic to Plumas County, California, where it is known from two occurrences in Lassen National Forest near Chester. There are approximately 250 individuals in existence. It grows in scrubby, forested mountain habitat, only on glaciated andesite substrates. This rare plant was discovered in 1997 and described to science as a new species in 2001.
Boechera perstellata is a rare species of flowering plant in the mustard family known by the common names Braun's rockcress and Nevada rockcress. It is native to Kentucky and Tennessee, where it is known from perhaps 25 total populations. Most of the occurrences have few individuals, and all are deteriorating in quality. The plant grows in shady forest habitat on limestone substrates, usually near streams or rivers. This is a federally listed endangered species of the United States.
Daphnopsis hellerana is a rare species of flowering plant in the genus Daphnopsis of the family Thymelaeaceae. It is endemic to Puerto Rico, where there were only four populations remaining in 1992, with a total of 125 individuals. It was federally listed as an endangered species of the United States in 1988.
Erigeron hessii is a rare species of flowering plant in the family Asteraceae known by the common name Hess' fleabane. It is endemic to New Mexico in the United States, where it is known from two locations in the Mogollon Mountains. It is found only in the Gila Wilderness.
