''Ceanothus pauciflorus'', known by the common name Mojave ceanothus, is a species of flowering

shrub A shrub (often also called a 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 tree ...

in the

buckthorn ''Rhamnus'' is a genus of about 110 accepted species of shrubs or small trees, commonly known as buckthorns, in the family Rhamnaceae. Its species range from tall (rarely to ) and are native mainly in east Asia and North America, but found thr ...

family,

Rhamnaceae The Rhamnaceae are a large family of flowering plants, mostly trees, shrubs, and some vines, commonly called the buckthorn family. Rhamnaceae is included in the order Rosales. The family contains about 55 genera and 950 species. The Rhamnaceae ...

. It is native to the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

(

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

, and

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

) and

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

, where it grows primarily in

shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It ...

communities at moderate to high elevations. It is characterized by oppositely arranged leaves, corky stipules and white flowers. It was formerly known as ''Ceanothus greggii''.

Description

''Ceanothus pauciflorus'' is a many-branched shrub with woody parts that are gray in color and somewhat woolly. The flowers bloom in spring.Blakely, Larry
Desert Ceanothus, Ceanothus greggii A. Gray var. vestitus (E. Greene) McMinn (Rhamnaceae)
, Who's in a Name? People Commemorated in Eastern Sierra Plant Names Blooms are considered highly fragrant. ''C. pauciflorus'' is eagerly browsed by

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to ani ...

and wild

ungulate Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, ...

s such as

mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whi ...

and

desert bighorn sheep The desert bighorn sheep (''Ovis canadensis nelsoni'') is a subspecies of bighorn sheep (''Ovis canadensis'') that is native to the deserts of the United States' intermountain west and southwestern regions, as well as northwestern Mexico. The ...

Morphology

This species is a

, around 0.2 to 4 m tall. The

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

is ascending to erect, and generally branches from at or near the base. The

twig A twig is a thin, often short, branch of a tree or bush. The buds on the twig are an important diagnostic characteristic, as are the abscission scars where the leaves have fallen away. The color, texture, and patterning of the twig bark ar ...

s are colored a pale gray to more or less white, and are densely

puberulent Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plan ...

to short-tomentose. The

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

leaves are arranged oppositely, on a petiole 1 to 3 mm long, and with a

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

5 to 20 mm long by 3 to 19 mm wide. The adaxial surface of the leaf is concave, colored gray-green to yellow-green, and puberulent, becoming glabrous (smooth) in age. The abaxial surface of the leaf is convex, colored gray-green, and is glabrous or has short, curly hairs. The tip of the leaf is generally shaped acute to obtuse. The margins of the leaf may have teeth. The stipule is a knob-like structure. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...

is a small (less than 2 cm long) cluster of many white

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s on short lateral branches. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in partic ...

is a horned capsule a few millimeters wide which bursts explosively to expel the three seeds inside, which require thermal

scarification Scarification involves scratching, etching, burning/branding, or superficially cutting designs, pictures, or words into the skin as a permanent body modification or body art. The body modification can take roughly 6–12 months to heal. In the ...

from

wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identi ...

before they can

germinate Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

Taxonomy

This species is a member of the ''Ceanothus''

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between ...

''Cerastes''.

Classification

This species was originally discovered to science by Spanish botanists

Martín Sessé y Lacasta Martín Sessé y Lacasta (December 11, 1751 – October 4, 1808) was a Spanish botanist, who relocated to New Spain (now Mexico) during the 18th century to study and classify the flora of the territory. Background Sessé studied medicine in Z ...

and

José Mariano Mociño José Mariano Mociño Suárez Lozano (24 September 1757 – 12 June 1820), or simply José Mariano Mociño, was a naturalist from New Spain. After having studied philosophy and medicine, he conducted early research on the botany, geology, and an ...

on an expedition to western Mexico in 1790 to 1791. It was later described as ''Ceanothus pauciflorus'' by

Augustin Pyramus de Candolle Augustin Pyramus (or Pyrame) de Candolle (, , ; 4 February 17789 September 1841) was a Swiss botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple of years de Candoll ...

in 1825, based on the illustrations made by Sessé and Mociño expedition. Sessé and Mociño also collected a flowering specimen of ''Ceanothus'', later determined to be ''Ceanothus pauciflorus.'' Because ''Ceanothus pauciflorus'' was the first description of the plant, subsequent descriptions were reduced to synonyms. It was named by

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

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of highe ...

in 1853 as ''Ceanothus greggii'' in honor of its collector, Josiah Gregg, who found the plant in 1847 at the site of the

Battle of Buena Vista The Battle of Buena Vista (February 22–23, 1847), known as the Battle of La Angostura in Mexico, and sometimes as Battle of Buena Vista/La Angostura, was a battle of the Mexican–American War. It was fought between the US invading forces, l ...

in the Mexican state of

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

during the

Mexican–American War The Mexican–American War, also known in the United States as the Mexican War and in Mexico as the (''United States intervention in Mexico''), was an armed conflict between the United States and Mexico from 1846 to 1848. It followed the ...

Edward Lee Greene Edward Lee Greene (August 20, 1843–November 10, 1915) was an American botanist known for his numerous publications including the two-part ''Landmarks of Botanical History'' and the describing of over 4,400 species of plants in the American W ...

named it as ''Ceanothus vestitus'', but recent taxonomic analysis finds that ''C. vestitus'' does not have enough morphological evidence to warrant a separate taxon from ''C. pauciflorus''.

Distribution and habitat

''Ceanothus pauciflorus'' is widely distributed throughout the

southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

and northern

. In the United States, it is found in the states of

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

, and

. It is widely distributed in Mexico, found from

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

and

south to

Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the Federative Entities of Mexico. It is divided into 570 municipaliti ...

. In Baja California, it is found from the Sierra Juarez to the Sierra de la Asamblea. However, it is replaced in a portion of its range in California and Baja California with a close relative, '' Ceanothus perplexans''. This species is found on a variety of habitats over its wide distribution, although it is almost always found in shrub-dominated communities like

chaparral Chaparral ( ) is a shrubland plant community and geographical feature found primarily in the U.S. state of California, in southern Oregon, and in the northern portion of the Baja California Peninsula in Mexico. It is shaped by a Mediterranea ...

and matorral at moderate to high elevations (550 to 2600 m).

References

External links

Calflora Database: ''Ceanothus greggii'' (desert ceanothus)Jepson Manual treatment of ''Ceanothus greggii''USDA Plants Profile for ''Ceanothus greggii'' (desert ceanothus)UC Photos gallery — ''Ceanothus greggii''
{{Taxonbar, from=Q59420238 pauciflorus Flora of California Flora of Northeastern Mexico Flora of Northwestern Mexico Flora of the South-Central United States Flora of the Southwestern United States Flora of the California desert regions Flora of the Sierra Nevada (United States) North American desert flora Natural history of the California chaparral and woodlands Natural history of the Mojave Desert Natural history of the Peninsular Ranges Natural history of the Transverse Ranges Plants described in 1825 Taxa named by Augustin Pyramus de Candolle Flora without expected TNC conservation status