Brassicaceae or Cruciferae is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The leaves are simple, lack stipules, and appear alternately on stems or in rosettes. The inflorescences are terminal and lack bracts. The flowers have four free sepals, four free alternating petals, two shorter free stamens and four longer free stamens. The fruit has seeds in rows, divided by a thin wall.
Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronomic techniques to either contain, remove or render toxic environmental contaminants harmless". The term is an amalgam of the Greek phyto (plant) and Latin remedium. Although attractive for its cost, phytoremediation has not been demonstrated to redress any significant environmental challenge to the extent that contaminated space has been reclaimed.
Salix viminalis, the basket willow, common osier or osier, is a species of willow native to Europe, Western Asia, and the Himalayas.
A hyperaccumulator is a plant capable of growing in soil or water with high concentrations of metals, absorbing these metals through their roots, and concentrating extremely high levels of metals in their tissues. The metals are concentrated at levels that are toxic to closely related species not adapted to growing on the metalliferous soils. Compared to non-hyperaccumulating species, hyperaccumulator roots extract the metal from the soil at a higher rate, transfer it more quickly to their shoots, and store large amounts in leaves and roots. The ability to hyperaccumulate toxic metals compared to related species has been shown to be due to differential gene expression and regulation of the same genes in both plants.
This list covers known nickel hyperaccumulators, accumulators or plant species tolerant to nickel.
This list covers hyperaccumulators, plant species which accumulate, or are tolerant of radionuclides, hydrocarbons and organic solvents, and inorganic solvents.
Streptanthus is a genus of plants within the family Brassicaceae. There are 58 known species within the genus Streptanthus, distributed through the western and south-central United States and northern Mexico. The common names for this genus are twistflower and jewelflower. Twenty-four of the species and eleven lesser taxa occur in California, thirty-two of which are California endemics; seventeen of these California taxa are classified as rare plants.
Streptanthus glandulosus subsp. niger is an endangered subspecies of flowering plant within the family Brassicaceae. Like other genus members, this herb has wavy petal margins with perimeter calluses that discourage larval herbivory. This plant is endemic to the Tiburon Peninsula of Northern California, and occurs at elevations below 150 m on serpentine grasslands. The common name for this subspecies is Tiburon jewelflower or black jewelflower. This annual herb blooms in May and June and displays dark purple sepals. The etymology of this genus scientific name derives from the Greek word streptanthus, meaning twisted flower, with reference to the notable wavy margins of the petals. The subspecies name niger relates to the color of the seeds being black, although an alternate account cites the dark color of the petals as the source of the appellation.
Streptanthus barbatus is a species of flowering plant in the mustard family known by the common name Pacific jewelflower. It is endemic to the southern Klamath Mountains of far northern California, where it occurs in open wooded habitat among Jeffrey Pines, generally on serpentine soils. It is a perennial herb producing a decumbent or erect, sometimes branching stem up to 70 to 90 centimeters long. It is hairless except for some light hairs on the flowers and the bases of the leaves. The largest leaves are at the base of the plant. They are oval with faintly toothed, bristly edges and borne on short petioles. Leaves above these are oval to rounded and may clasp the stem. Flowers occur at intervals along the upper stem. Each has a spherical to urn-shaped calyx of keeled sepals under a centimeter long with curving petals barely emerging from the tip. The calyx of sepals is whitish, darkening purple in maturity. The petals are purple. The fruit is a long, flat, curving silique which may be 7 centimeters in length.
Streptanthus breweri is a species of flowering plant in the mustard family known by the common name Brewer's jewelflower. It is endemic to California, where it can be found in the coastal mountain ranges from the Klamath Mountains south to the San Francisco Bay Area. Its habitat includes chaparral and woodlands, usually on serpentine soils. It is an annual herb producing an erect, branching stem up to about 80 centimeters in maximum height. It is hairless except for fine hairs on some of the inflorescence parts, and it may be waxy in texture. The basal leaves have oval blades borne on petioles, and the lance-shaped leaves farther up the stem clasp it at their bases. Flowers occur at intervals along the upper stem, sometimes in a zig-zagging, one-sided array. Each has an urn-shaped calyx of keeled greenish or purplish sepals under a centimeter long. White, purple, or purple-veined white petals emerge from the tip. The fruit is a narrow, curved silique which may be 9 to 11 centimeters in length.
Streptanthus cordatus is a species of flowering plant in the mustard family known by the common name heartleaf twistflower. It is native to the western United States, where it can be found in many types of sagebrush, woodland, and forest habitat. It is a perennial herb producing a branched or unbranched stem up to about a meter tall. It is often waxy in texture. The basal leaves are oval or spoon-shaped with bristle-toothed blades borne on rough-haired petioles. Leaves higher on the stem are oval to lance-shaped, up to 9 centimeters long with their bases usually clasping the stem. Flowers occur at intervals along the upper stem. Each has a calyx of sepals roughly a centimeter long which begin greenish yellow and mature purple. Four purple petals emerge from the tip of each calyx. The fruit is a thin, narrow silique which may reach 14 centimeters in length or longer.
Streptanthus glandulosus is a species of flowering plant in the mustard family known by the common name bristly jewelflower. It is native to California and southwestern Oregon, where it grows in many types of habitat, including grassland, chaparral, and woodlands. Genetic and other analyses indicate that it is a species complex with ten subspecies which evolved as populations were isolated from each other. The complex includes subspecies previously considered separate species, such as the rare Tiburon jewelflower endemic to the San Francisco Bay Area. Plants in the complex are variable. In general they are annual herbs growing 10 centimeters to over a meter in height. They may be hairless hairy to bristly. The ephemeral basal leaves have blades borne on winged petioles. Leaves higher on the stem are linear to lance-shaped and clasp the stem at their bases. Flowers occur at intervals along the upper stem. Each flower has an urn-shaped calyx of sepals one-half to over one centimeter long which can be almost any color from white to yellowish to pink or purple to nearly black. Purple, white, or purple-veined white petals emerge from the tip. The fruit is a straight or curving silique up to 11 centimeters long.
Streptanthus howellii is an uncommon species of flowering plant in the mustard family known by the common name Howell's jewelflower. It is endemic to the Klamath Mountains of southern Oregon and northern California. It grows in mountain forests on serpentine soils. It is a perennial herb producing a hairless, often waxy-textured stem up to 70 or 80 centimeters in maximum length. It is generally unbranched. The ephemeral basal leaves have fleshy oval blades with smooth or toothed edges, borne on petioles. Leaves farther up the stem are similar but smaller and narrower, with shorter petioles or none. They do not clasp the stem. Flowers occur at intervals along the upper stem. Each has a calyx of purple sepals under a centimeter long with purple-tipped yellow petals emerging from the tip. The fruit is a thin, smooth, curved silique up to 12 centimeters long.
Streptanthus longisiliquus is a species of flowering plant in the mustard family known by the common name long-fruit jewelflower. It was first described to science in 2007. It is endemic to northern California, where it is known from Butte, Tehama, and Shasta Counties. It can be found in forest and woodland habitat in mountains and foothills. It is a short-lived perennial herb producing a few-branched stem up to 1.2 to 1.5 meters in maximum height. It is mostly hairless except for some light hairs on the inflorescences and sometimes the leaf petioles. The basal leaves have oval or spoon-shaped blades up to 10 centimeters long, usually with smooth edges. Leaves higher on the stem are oval or oblong and lack petioles, their bases often clasping the stem. Flowers occur at intervals along the upper stem. Each flower has a bell-shaped calyx of sepals which yellow-green at the base and purplish at the tip, measuring under a centimeter in length. The petals emerging from the end are brownish or purplish with greenish bases. The fruit is a flattened, curving silique that can be quite long even for the genus, measuring up to 15 centimeters in length.
Streptanthus vernalis is a rare species of flowering plant in the mustard family known by the common name early jewelflower. It was first observed in the 1970s but not actually described to science until 2005. It is endemic to Lake County, California, where it is known from a single occurrence at Three Peaks near the Napa County line. It is apparently limited to serpentine outcrops in forested and chaparral habitat. Genetic analysis indicates that the species is distinct from other Streptanthus and is most closely related to Streptanthus morrisonii, which it resembles. It is a hairless annual herb producing an erect branching or unbranched stem 2 to 20 centimeters tall. The ephemeral basal leaves have thick, fleshy leaves which are green and unmottled on top and purple on the undersides. Leaves higher on the stem are linear to lance-shaped and lack petioles. Flowers occur at intervals along the upper stem. Each flower has an urn-shaped calyx of sepals which is solid green with no purple or yellowish tinge. The petals emerging from the tip are white without darker veining. The fruit is a flattened straight silique 3 to 5 centimeters long containing orange seeds.
Streptanthus morrisonii is an uncommon species of flowering plant in the mustard family known by the common name Morrison's jewelflower. It is endemic to California, where it is known from the North and Central Coast Ranges. It is limited to serpentine soils in chaparral and forest habitat. It is considered a species complex which includes Streptanthus brachiatus. S. morrisonii is divided into four subspecies and is variable. In general, it is a biennial herb producing a hairless, waxy stem up to 1.2 to 1.5 meters in maximum height, often branching at the tip. The basal leaves have fleshy, lance-shaped blades 3 to 5 centimeters long borne on petioles. The blades are gray-green on the upper surface and purple or purple-mottled underneath. Leaves higher on the stem are variable in shape and become smaller toward the top of the plant. Flowers occur at intervals along the upper stem. Each has an urn-shaped calyx of keeled sepals in shades of yellow-green to purple. The petals emerging from the tip are whitish with purple-brown veining. The fruit is a flattened straight or slightly curved silique up to 8 centimeters long.
Streptanthus tortuosus is a biennial or short lived perennial plant in the mustard family (Brassicaceae) known by the common names shieldplant, shieldleaf, and mountain jewelflower.
Sibaropsis is a monotypic genus of flowering plants in the family Brassicaceae containing the single species Sibaropsis hammittii, which is known by the common name Hammitt's clay-cress. It is endemic to California, where it is known from two locations in the Peninsular Ranges. The plant is known from the Santa Ana Mountains of Riverside County and Viejas Mountain and nearby peaks east of San Diego. It grows in grassy habitat in openings in chaparral alongside purple needlegrass, generally in moist areas in heavy clay soils. This species and its genus were first described to science in 1997.
