''Cneoridium'' is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus in the citrus family which contains the single species ''Cneoridium dumosum'', commonly known as bushrue or coast spice bush. As a

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

shrub, ''Cneoridium'' is native to the coast of

southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

and

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, thriving in hot, dry conditions. This plant is characterized by a distinctive citrusy aroma and small, white flowers that appear from winter to spring. The flowers eventually become round berries that resemble a miniature version of the common

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

. Widely known and utilized by the

indigenous peoples of the Americas In the Americas, Indigenous peoples comprise the two continents' pre-Columbian inhabitants, as well as the ethnic groups that identify with them in the 15th century, as well as the ethnic groups that identify with the pre-Columbian population of ...

for centuries, this species was first discovered and introduced to

Western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...

science by

Thomas Nuttall Thomas Nuttall (5 January 1786 – 10 September 1859) was an English botanist and zoologist who lived and worked in America from 1808 until 1841. Nuttall was born in the village of Long Preston, near Settle in the West Riding of Yorkshire a ...

, on his trip to

San Diego San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...

. Today, this species is listed as imperiled, as some of its habitats are threatened by coastal development,

urbanization Urbanization (or urbanisation in British English) is the population shift from Rural area, rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. ...

, military operations and

fire suppression Fire suppression may refer to: * Firefighting * Fire suppression systems * Wildfire suppression Wildfire suppression is a range of firefighting tactics used to suppress wildfires. Firefighting efforts depend on many factors such as the availabl ...

. It has also found its way into

horticultural Horticulture (from ) is the art and science of growing fruits, vegetables, flowers, trees, shrubs and ornamental plants. Horticulture is commonly associated with the more professional and technical aspects of plant cultivation on a smaller and mo ...

circles in its native regions, providing gardeners with a low-maintenance shrub that gives off rewarding flowers. Despite attractive qualities like its distinctive fragrance and flowers, this species may cause blistering and burning rashes to people after contact with its foliage, a phenomenon common with members of the citrus family, known as

phytophotodermatitis Phytophotodermatitis, also known as berloque dermatitis,, margarita photodermatitis,, lime disease or lime phytodermatitis is a cutaneous phototoxic inflammatory reaction resulting from contact with a light-sensitizing botanical agent (such as ...

Description

This

, intricately branched

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

may exceed a meter and a half in height and sprawl about as wide, with a rounded form. Its twigs are covered in small, linear to oblong- shaped green

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

1 to 2.5 cm in length and arranged opposite of each other. The leaves are glabrous and are dotted with small

glands A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also funct ...

. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is a cyme or cluster with 1 to 3 flowers. Each

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

is just over a centimeter wide with four or rarely five rounded white

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

s and eight yellow-anthered white

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s. The leaves of this plant are aromatic, while the flowers also give off a fragrance described as a "wonderful citrusy sweet perfume." The bunching fruits are round green

berries A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone fruit, stone or pit (fruit), pit although many wikt:pip#Etymology 2, pips or seeds may be p ...

about half a centimeter wide covered in a thin peel which is gland-pitted like that of a common citrus fruit. In age the berries change to a reddish to brown color. Each berry contains one or two spherical seeds.

Phytochemistry

Numerous chemicals have been isolated from this plant, including osthol, imperatorin, isoimperatorin,

bergapten Bergapten (5-methoxypsoralen) is a naturally-occurring organic chemical compound produced by numerous plant species, especially from the carrot family Apiaceae and the citrus family Rutaceae. For example, bergapten has been extracted from 24 ...

, isopimpinellin, xanthotoxin, justicidin A and

marmesin Marmesin (nodakenetin) is a chemical compound precursor in psoralen and linear furanocoumarins biosynthesis. Marmesin plays a central role in the biosynthesis of furocoumarins in the plant ruta graveolens, more commonly known as rue. It acts as ...

. This plant is also capable of causing

on humans after skin contact, and it can sometimes be severe if exposure is for several hours. After the plant's foliage is contacted, light-sensitizing chemicals in the oils of the plant combined with ultraviolet radiation initiate an inflammatory reaction that can present as a burning, blistering rash. This effect is variable from person to person, with some people not blistering at all.

Taxonomy

Taxonomic history and classification

This species was first discovered to

science by

, an English botanist and naturalist. Nuttall had arrived in

aboard the hide ship ''Pilgrim'', staying in the harbor for three weeks as he waited for a Bryant and Sturgis ship to sail him back to

Boston Boston is the capital and most populous city in the Commonwealth (U.S. state), Commonwealth of Massachusetts in the United States. The city serves as the cultural and Financial centre, financial center of New England, a region of the Northeas ...

. Nuttall was one of few naturalists to set foot in the region at the time, being preceded by

Menzies Menzies is a Scottish surname, with Gaelic forms being Méinnearach and Méinn, and other variant forms being Menigees, Mennes, Mengzes, Menzeys, Mengies, and Minges. Derivation and history The name and its Gaelic form are probably derived f ...

, Botta, Coulter, and Deppe, all of whom had only stopped in San Diego briefly. In Nuttall's stay in San Diego, he collected around 44 species of plants. Nuttall likely encountered this species on

Point Loma Point Loma ( Spanish: ''Punta de la Loma'', meaning "Hill Point"; Kumeyaay: ''Amat Kunyily'', meaning "Black Earth") is a seaside community in San Diego, California, United States. Geographically it is a hilly peninsula that is bordered on the ...

, as he spent extensive time on the peninsula (for it was the original anchorage in

San Diego Bay San Diego Bay is a natural harbor and deepwater port in San Diego County, California, near the Mexico–United States border. The bay, which is long and wide, is the third largest of the three large, protected natural bays on California's of ...

) and it is home to an abundant population of this plant. From Nuttall's work, eminent North American botanists

John Torrey John Torrey (August 15, 1796 – March 10, 1873) was an American botany, botanist, chemist, and physician. Throughout much of his career, he was a teacher of chemistry, often at multiple universities, while he also pursued botanical work, focus ...

and

Asa Gray Asa Gray (November 18, 1810 – January 30, 1888) is considered the most important American botany, botanist of the 19th century. His ''Darwiniana'' (1876) was considered an important explanation of how religion and science were not necessaril ...

described this species as ''Pitavia dumosa'' in their ''Flora of North America''. However, the pair had failed to find Nuttall's notes on the plant, and had to describe this species based on incomplete specimens. The botanists also noted that this species appeared to differ from the '' Pitavia'' genus as circumscribed by Jussieu. Botanist

Joseph Dalton Hooker Sir Joseph Dalton Hooker (30 June 1817 – 10 December 1911) was a British botanist and explorer in the 19th century. He was a founder of geographical botany and Charles Darwin's closest friend. For 20 years he served as director of the Ro ...

later combined this species into ''Cneoridium dumosum'', but he produced a ''nomen invalidum'' ( invalid name) as he failed to specify the

rank A rank is a position in a hierarchy. It can be formally recognized—for example, cardinal, chief executive officer, general, professor—or unofficial. People Formal ranks * Academic rank * Corporate title * Diplomatic rank * Hierarchy ...

Henri Ernest Baillon Henri Ernest Baillon (; 30 November 1827 in Calais – 19 July 1895 in Paris) was a French botanist and physician. Baillon spent his academic career teaching natural history and publishing numerous works on botany. He was appointed to the Lé ...

later corrected Hooker's mistake in 1873, with the fourth volume of his publication ''Histoire des Plantes'', leading to the current name ''Cneoridium dumosum'' (Nutt.) Hook.f. ex Baill. The genus ''Cneoridium'' is placed in the subfamily

Amyridoideae ''Amyridoideae'' is a subfamily of the family Rutaceae. The circumscription of the family has varied considerably. A 2014 classification placed a large proportion of the genera in the family Rutaceae in Amyridoideae. A more recent 2021 classifica ...

, placing it as a close relative to '' Amyris'', its

sister clade In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

, and '' Stauranthus.'' The three genera also share morphological features, such as their fleshy fruits, characterized in this genus by the berries.

Etymology

The generic name ''Cneoridium'' derives from the diminutive form of '' Cneorum'', the spurge olive, which in turn comes from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''kneoron'', which was applied to some dwarf shrubs resembling the olive. The first letter of ''Cneoridium'' is silent, with the name pronounced like "Nee-oh-rí-di-um." The specific epithet ''dumosum'' is derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''dūmōsus'', which means bushy or shrubby. The common name "spice bush" likely refers to the shrub's aromatic leaves.

Distribution and habitat

This species is distributed within the states of

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. In California, this species occurs on the southern coast in

and

Orange Orange most often refers to: *Orange (fruit), the fruit of the tree species '' Citrus'' × ''sinensis'' ** Orange blossom, its fragrant flower ** Orange juice *Orange (colour), the color of an orange fruit, occurs between red and yellow in the vi ...

counties, and on

San Clemente Island San Clemente Island (Tongva: ''Kinkipar''; Spanish: ''Isla de San Clemente'') is the southernmost of the Channel Islands of California. It is owned and operated by the United States Navy, and is a part of Los Angeles County. It is administer ...

. In Baja California, this species is found throughout the northwestern portion of the state south to the

central desert Deserts cover about , or 18%, of the Australian mainland, but about 35% of the Australian continent receives so little rain, it is practically desert. Collectively known as the Great Australian desert, they are primarily distributed throughout ...

. It also has a disjunct distribution in the Sierra de San Borja near

Bahia de Los Angeles Bahia () is one of the 26 states of Brazil, located in the Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo, Minas Gerais, and Rio de Janeiro) and the 5th-largest by area. Bahia's capita ...

in southern Baja California. Plants of this species primarily occur on bluffs, mesa, hillsides and washes near the coast, and the slightly inland foothills of the

Peninsular Ranges The Peninsular Ranges (also called the Lower California province) are a group of mountain ranges that stretch from Southern California to the southern tip of the Baja California peninsula; they are part of the North American Pacific Coast Range ...

. It is found in

chaparral Chaparral ( ) is a shrubland plant plant community, community found primarily in California, southern Oregon, and northern Baja California. It is shaped by a Mediterranean climate (mild wet winters and hot dry summers) and infrequent, high-intens ...

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 ...

and coastal succulent scrub habitats below 1000 meters. This plant is considered to play an important role in the habitat for the San Quintin Quail ( ''Callipepla californica'' subsp. ''plumbea'').

Uses

Cultivation

Introduced into cultivation by Theodore Payne, this diminutive woody shrub has a reputation of being difficult to establish, but given proper care it is a long-lived, slow-growing plant that thrives on neglect. Native to a large number of habitats, from the moist coast to the dry inland hills, it is adaptable to

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

. It tolerates hot, dry climates with some afternoon shade, often staying green with no water after establishment. It may be watered sparingly during the hot season to help keep the leaves more vibrantly green. It is also recommended to keep plants away from pathways because of the risk of phytophotodermatitis triggered by the foliage. Although more commonly grown by nurseries for

habitat restoration Ecological restoration, or ecosystem restoration, is the process of assisting the recovery of an ecosystem that has been degraded, damaged, destroyed or transformed. It is distinct from conservation in that it attempts to retroactively repair ...

, bushrue can be utilized in local native gardens, with their moderate size compatible with small gardens. It often goes dormant in summer, with the leaves becoming dull green, and in the fall or winter they may turn yellow or orange with frost. This plant will frequently bloom in winter to spring, with rewarding January flowers. This plant can be propagated by cuttings or

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

. Cuttings must be taken in winter or spring from stems at least 1 year old, and treated with rooting hormone after the foliage is removed from the bottom half of the cutting. Cuttings are then placed in a mix of half

peat Peat is an accumulation of partially Decomposition, decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, Moorland, moors, or muskegs. ''Sphagnum'' moss, also called peat moss, is one of the most ...

and half moist

perlite Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the Hydrate, hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an indu ...

, watered, and situated in a plastic bag that is not entirely sealed. The plastic bag is then placed in a warm spot with indirect sunlight. To propagate from seed, berries must be picked when they are a distinctive chocolate-brown color at the end of summer. Seed germination rates can approach 100% when they are also

stratified Stratification may refer to: Mathematics * Stratification (mathematics), any consistent assignment of numbers to predicate symbols * Data stratification in statistics Earth sciences * Stable and unstable stratification * Stratification, or st ...

at 55 °F for a couple of weeks.

Ethnobotany

This species was utilized for medicinal purposes by the indigenous

Luiseño The Luiseño or Payómkawichum are an Indigenous people of California who, at the time of the first contacts with the Spanish in the 16th century, inhabited the coastal area of southern California, ranging from the present-day southern part of ...

and

Kumeyaay The Kumeyaay, also known as 'Iipai-Tiipai or by the historical Spanish name Diegueño, is a tribe of Indigenous peoples of the Americas who live at the northern border of Baja California in Mexico and the southern border of California in the Uni ...

peoples for centuries. The Luiseño would make an infusion by boiling the leaves of this plant, noting that it had a blood-thinning effect that included diuretic action. They would also use it to cure earaches, by placing the raw leaves in the ear with a small amount of warm olive oil. Delfina Cuero of the Kumeyaay people reported using the boiled plant as a

mouthwash Mouthwash, mouth rinse, oral rinse, or mouth bath is a liquid which is held in the mouth passively or swirled around the mouth by contraction of the perioral muscles and/or movement of the head, and may be gargled, where the head is tilted back ...

and gargle, and also for

toothache Toothaches, also known as dental pain or tooth pain,Segen JC. (2002). ''McGraw-Hill Concise Dictionary of Modern Medicine''. The McGraw-Hill Companies. is pain in the teeth or their supporting structures, caused by dental diseases or referred ...

Gallery

File:Cneoridium dumosum 59668373.jpg, Flowering in habitat File:Cneoridium dumosum 120150255.jpg, Flowers with berries File:Cneoridium dumosum 73339797.jpg, The unripe red and green berries File:C. dumosum 2.jpg, Flowers with foliage File:Cneoridium dumosum 139607075.jpg, The berries, after turning brown in the summer sun

References

External links

Jepson Manual Treatment - ''Cneoridium dumosum''

USDA Plants Profile

Cneoridium dumosum - Photo gallery
{{Taxonbar, from1=Q15930442, from2=Q5137348 Flora of California Flora of Baja California Rutaceae Monotypic Rutaceae genera Taxa named by Henri Ernest Baillon Taxa named by William Jackson Hooker Taxa named by Thomas Nuttall Plants used in traditional Native American medicine