''Ceanothus'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of about 50–60 species of
nitrogen-fixing
Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atm ...
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 trees ...
s and small
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...
s in the
buckthorn family (
Rhamnaceae).
[ Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus.][ ''"Ceanothus"'' comes from grc, κεάνωθος (''keanōthos''), which was applied by ]Theophrastus
Theophrastus (; grc-gre, Θεόφραστος ; c. 371c. 287 BC), a Greek philosopher and the successor to Aristotle in the Peripatetic school. He was a native of Eresos in Lesbos.Gavin Hardy and Laurence Totelin, ''Ancient Botany'', Routledge ...
(371–287 BC) to an Old World plant believed to be ''Cirsium arvense
''Cirsium arvense'' is a perennial species of flowering plant in the family Asteraceae, native throughout Europe and western Asia, northern Africa and widely introduced elsewhere.Joint Nature Conservation Committee''Cirsium arvense'' The standa ...
''.
The genus is native to North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
with the highest diversity on the western coast.[ Some species (e.g., '' C. americanus'') are restricted to the eastern United States and southeast Canada, and others (e.g., '' C. caeruleus'') extend as far south as Guatemala. Most are shrubs tall, but '' C. arboreus'' and '' C. thyrsiflorus'', both native to California, can be small multi-trunked trees up to tall.
]
Taxonomy and etymology
There are two subgenera within this genus: ''Ceanothus'' and ''Cerastes''. The former clade is less drought-resistant, having bigger leaves. The evolution of these two clades likely started with a divergence in the niches filled in local communities, rather than a divergence on the basis of geography.
The Californian species of ''Ceanothus'' are commonly known collectively as California lilacs, with individual species having more descriptive common names. Species native elsewhere have other common names such as New Jersey tea for ''C. americanus'', as its leaves were used as a black tea substitute during the American Revolution.[
] In garden use, most are simply called by their scientific names or an adaptation of the scientific name, such as 'Maritime ceanothus' for ''C. maritimus''.
Species
, accepted species are:
* ''Ceanothus americanus
''Ceanothus americanus'' is a species of ''Ceanothus'' shrub native to North America. Common names include New Jersey tea, Jersey tea ceanothus, variations of red root (red-root; redroot), mountain sweet (mountain-sweet; mountainsweet), and wild ...
'' L. – New Jersey tea; red root
* ''Ceanothus arboreus
''Ceanothus arboreus'' is a species of perennial shrub to small tree in the family Rhamnaceae, commonly known as the feltleaf ceanothus, island ceanothus, and island mountain lilac. It is the largest member of the California lilacs (the ''Ceanot ...
'' Greene – feltleaf ceanothus
* ''Ceanothus arcuatus
''Ceanothus'' is a genus of about 50–60 species of nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus. ''"Ceanothus ...
'' McMinn
* ''Ceanothus bolensis
''Ceanothus'' is a genus of about 50–60 species of nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus. ''"Ceanothus ...
'' S.Boyd & J.E.Keeley
* ''Ceanothus buxifolius
''Ceanothus'' is a genus of about 50–60 species of nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus. ''"Ceanothus ...
'' Willd. ex Schult. & Schult.f.
* '' Ceanothus caeruleus'' Lag
* ''Ceanothus confusus
''Ceanothus confusus'' is a species of shrub in the family Rhamnaceae known by the common name Rincon Ridge ceanothus. It is endemic to northern California where it grows in the coastal mountains north of the San Francisco Bay Area. Its habita ...
'' J.T. Howell – Rincon Ridge ceanothus
* ''Ceanothus connivens
''Ceanothus'' is a genus of about 50–60 species of Actinorhizal plant, nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceano ...
'' Greene – trailing buckbrush
* ''Ceanothus cordulatus
''Ceanothus cordulatus'' is a species of shrub in the family Rhamnaceae known by the common names mountain whitethorn and whitethorn ceanothus. It is native to California and adjacent sections of Oregon, Nevada, and Baja California, where it gr ...
'' Kellogg – whitethorn ceanothus
* ''Ceanothus crassifolius
''Ceanothus crassifolius'' is a species of flowering shrub known by the common name hoaryleaf ceanothus. This ''Ceanothus'' is found throughout the coastal mountain ranges of the southern half of California, and its range extends into Baja Calif ...
'' Torr. – hoaryleaf ceanothus
* ''Ceanothus cuneatus
''Ceanothus cuneatus'' is a species of flowering shrub known by the common names buckbrush and wedgeleaf ceanothus.
Distribution
This ''Ceanothus'' is native to Oregon, California, and northern Baja California, where it can be found in a number ...
'' (Hook.) Nutt. – buckbrush
** subsp. ''cuneatus'' (Hook.) Nutt.
** subsp. ''fascicularis'' (McMinn) C.L.Schmidt
** subsp. ''rigidus'' (Nutt.) C.L.Schmidt
** subsp. ''sonomensis'' (Howell) C.L.Schmidt
* ''Ceanothus cyaneus
''Ceanothus cyaneus'' is a species of flowering shrub in the genus ''Ceanothus'' known commonly as the San Diego buckbrush and Lakeside ceanothus. This species is found in the Peninsular Ranges of San Diego County, California, and known from one ...
'' Eastw. – San Diego buckbrush
* ''Ceanothus decornutus
''Ceanothus'' is a genus of about 50–60 species of nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus. ''"Ceanothus ...
'' V.T.Parker
* ''Ceanothus dentatus
''Ceanothus dentatus'' is a species of shrub in the family Rhamnaceae known by the common name sandscrub ceanothus. It is endemic to California, where it is known only from the Central Coast and its Coast Ranges. It grows in coastal hills, blu ...
'' Torr. & A.Gray – sandscrub ceanothus
* ''Ceanothus depressus
''Ceanothus depressus'' Benth.Bentham, Planta Hartwegiana 8. 1839. is a shrub in the family Rhamnaceae, native to the Mexican states of Chihuahua and Sonora. It is a shrub up to 70 cm tall, growing in clearings in pine-oak forests.
Uses
...
'' Benth. – junco
* ''Ceanothus divergens
''Ceanothus divergens'', commonly known as Calistoga ceanothus, is an evergreen shrub in the family Rhamnaceae, an endemic of California.
Description
This plant has a growth habit described as ascending to erect and may attain height. The pla ...
'' Parry – Calistoga ceanothus
* '' Ceanothus diversifolius'' Kellogg – pinemat
* ''Ceanothus fendleri
''Ceanothus fendleri'' (Fendler sceanothus, Fendler sbuckbrush, deer brier) is a species of flowering shrub native to northern Mexico, Arizona, New Mexico, west Texas and the northeastern Texas panhandle, Utah, Colorado, eastern Wyoming, and wes ...
'' A.Gray – Fendler's ceanothus
* '' Ceanothus ferrisiae'' McMinn – coyote ceanothus
* '' Ceanothus foliosus'' Parry – wavyleaf ceanothus
** subsp. ''foliosus'' Parry
** subsp. ''medius'' (McMinn) C.L.Schmidt
** subsp. ''vineatus'' (McMinn) C.L.Schmidt
* '' Ceanothus fresnensis'' Dudley ex Abrams – Fresno ceanothus
* '' Ceanothus gloriosus'' J.T. Howell – Point Reyes ceanothus
** subsp. ''exaltatus'' (Howell) C.L.Schmidt
** subsp. ''gloriosus'' J.T. Howell
** subsp. ''masonii'' (McMinn) C.L.Schmidt
** subsp. ''porrectus'' (Howell) C.L.Schmidt
* '' Ceanothus griseus'' (Trel. ex B.L.Rob.) McMinn – Carmel ceanothus
* ''Ceanothus hearstiorum
''Ceanothus hearstiorum'' is a species of flowering shrub known by the common names Hearst Ranch buckbrush and Hearst's ceanothus. This '' Ceanothus'' is endemic to California, where it grows wild only on the hilly coastline of San Luis Obispo C ...
'' Hoover & J.B.Roof – Hearst Ranch buckbrush
* ''Ceanothus herbaceus
''Ceanothus herbaceus'', also known as Jersey tea, is a species of shrub in the family Rhamnaceae and is similar to ''Ceanothus americanus'' and ''Ceanothus sanguineus''. It is a perennial shrub which is native to North America.
Synonyms
As fo ...
'' Raf. – Jersey tea
* '' Ceanothus impressus'' Trel. – Santa Barbara ceanothus
* '' Ceanothus incanus'' Torr. & A.Gray – coast whitethorn
* '' Ceanothus integerrimus'' Hook. & Arn. – deerbrush ceanothus
* ''Ceanothus jepsonii
''Ceanothus jepsonii'' is a species of shrub in the family Rhamnaceae known by the common names musk brush and Jepson ceanothus.
Description
This species of shrub is variable, particularly across its two varieties:
*''Ceanothus jepsonii'' va ...
'' Greene – Jepson ceanothus
** subsp. ''albiflorus'' (Howell) C.L.Schmidt
** subsp. ''jepsonii'' Greene
* '' Ceanothus lanuginosus'' (M.E.Jones) Rose
* '' Ceanothus lemmonii'' Parry – Lemmon's ceanothus
* '' Ceanothus leucodermis'' Greene – chaparral whitethorn
* '' Ceanothus maritimus'' Hoover – maritime ceanothus
* '' Ceanothus martinii'' M.E.Jones – Martin's ceanothus
* '' Ceanothus masonii'' McMinn – Mason's ceanothus
* '' Ceanothus megacarpus'' Nutt. – bigpod ceanothus
** subsp. ''insularis'' (Eastw.) P.H.Raven
** subsp. ''megacarpus'' Nutt.
* '' Ceanothus microphyllus'' Michx. – littleleaf buckbrush
* '' Ceanothus ochraceus'' Suess.
* '' Ceanothus oliganthus'' Nutt. – hairy ceanothus
** subsp. ''oliganthus'' Nutt.
** subsp. ''sorediatus'' (Hook. & Arn.) C.L.Schmidt
* '' Ceanothus ophiochilus'' Boyd, Ross & Arnseth – Vail Lake ceanothus
* '' Ceanothus otayensis'' H. E. McMinn – Otay Mountain buckbrush
* '' Ceanothus palmeri'' Trel. – Palmer ceanothus
* ''Ceanothus papillosus
''Ceanothus papillosus'', the wartleaf ceanothus, is a species of plant in the genus ''Ceanothus''. It is Endemism, endemic to California, where it grows in open habitat on the slopes of the coastal mountain ranges, such as woodland and chaparral ...
'' Torr. & A.Gray – wartleaf ceanothus
* '' Ceanothus parryi'' Trel. – Parry Ceanothus
* '' Ceanothus parvifolius'' (S.Watson) Trel. – littleleaf ceanothus
* '' Ceanothus pauciflorus'' DC.
* '' Ceanothus pendletonensis'' D.O.Burge, Rebman, & M.R.Mulligan
* '' Ceanothus perplexans'' Trel.
* ''Ceanothus pinetorum
''Ceanothus pinetorum'' is a species of shrub in the family Rhamnaceae known by the common names Kern ceanothus and Coville ceanothus. It is endemic to the Sierra Nevada of California, where it is known only from the Kern Plateau, a section o ...
'' Coville – Coville ceanothus
* ''Ceanothus prostratus
''Ceanothus prostratus'' is a species of shrub in the family Rhamnaceae. Common names include prostrate ceanothus, pinemat, and mahala mat. It is native to the Pacific Northwest of the United States where it grows in coniferous forests and open ...
'' Benth. – prostrate ceanothus
** subsp. ''confusus'' (Howell) C.L.Schmidt
** subsp. ''prostratus'' Benth.
** subsp. ''pumilus'' (Greene) C.L.Schmidt
* '' Ceanothus pumilus'' Greene – dwarf ceanothus
* '' Ceanothus purpureus'' Jepson – hollyleaf ceanothus
** subsp. ''divergens'' (Parry) C.L.Schmidt
** subsp. ''purpureus'' Jepson
* ''Ceanothus roderickii
''Ceanothus roderickii'' is a rare species of shrub in the family Rhamnaceae known by the common name Pine Hill ceanothus. It is endemic to western El Dorado County, California, where it grows in the chaparral and woodlands of the Sierra Neva ...
'' Knight – Pine Hill buckbrush
* ''Ceanothus sanguineus
''Ceanothus sanguineus'' is a species of shrub in the family Rhamnaceae known by the common name redstem ceanothus. It is native to western North America from British Columbia to Montana to far northern California; it is also known from Michigan. ...
'' Pursh – redstem ceanothus
* '' Ceanothus serpyllifolius'' Nutt. – Coastal Plain buckbrush
* '' Ceanothus sonomensis'' J.T. Howell – Sonoma ceanothus
* '' Ceanothus spinosus'' Nutt. – green bark ceanothus
* ''Ceanothus thyrsiflorus
''Ceanothus thyrsiflorus'', known as blueblossom or blue blossom ceanothus, is an evergreen shrub in the buckthorn family Rhamnaceae that is endemism, endemic to Oregon and California in the US. The term 'Californian lilac' is also applied to thi ...
'' Eschsch. – blueblossom
* '' Ceanothus tomentosus'' Parry – woolyleaf ceanothus
* ''Ceanothus velutinus
''Ceanothus velutinus'', with the common names snowbrush ceanothus, red root, and tobacco brush, is a species of shrub in the family Rhamnaceae. It is native to western North America from British Columbia to California to Colorado, where it gro ...
'' Dougl. ex Hook. – snowbrush ceanothus
** subsp. ''laevigatus'' (Torr. & A.Gray) Piper & Beattie
** subsp. ''velutinus'' Dougl. ex Hook.
* '' Ceanothus verrucosus'' Nutt. – Barranca brush
Species names with uncertain taxonomic status
The status of the following species is unresolved:
* ''Ceanothus atropurpureus'' Raf.
* ''Ceanothus chloroxylon'' Nees
* ''Ceanothus collinus'' Douglas ex Knowles & Westc.
* ''Ceanothus cuneatus'' A.Gray
* ''Ceanothus cuneatus'' K.Brandegee
* ''Ceanothus divergens'' Poepp. ex Endl.
* ''Ceanothus elongatus'' Salisb.
* ''Ceanothus flexilis'' McMinn
* ''Ceanothus glaber'' Spach
* ''Ceanothus laevigatus'' Howell
* ''Ceanothus lancifolius'' Moench
* ''Ceanothus leschenaultii'' DC.
* ''Ceanothus mocinianus'' DC.
* ''Ceanothus mystacinus'' DC.
* ''Ceanothus neumannii'' Tausch
* ''Ceanothus oblanceolatus'' Davidson
* ''Ceanothus pauciflorus'' Moc. & Sessé ex DC.
* ''Ceanothus pubiflorus'' DC.
* ''Ceanothus pulchellus'' Delile ex Spach
* ''Ceanothus scandens'' D.Dietr.
* ''Ceanothus spathulatus'' Labill.
* ''Ceanothus spinosus'' Torr. & A. Gray
* ''Ceanothus triqueter'' Wall.
* ''Ceanothus vanrensselaeri'' Roof
Hybrids
The following hybrids have been described:
* ''Ceanothus'' × ''arcuatus'' McMinn
* ''Ceanothus'' × ''bakeri'' Greene ex McMinn
* ''Ceanothus'' × ''flexilis'' McMinn
* ''Ceanothus'' × ''lobbianus'' Hook.
* ''Ceanothus'' × ''lorenzenii'' (Jeps.) McMinn
* ''Ceanothus'' × ''mendocinensis'' McMinn
* ''Ceanothus'' × ''otayensis'' McMinn
* ''Ceanothus'' × ''rugosus'' Greene
* ''Ceanothus'' × ''serrulatus'' McMinn
* ''Ceanothus'' × ''vanrensselaeri'' Roof
* ''Ceanothus'' × ''veitchianus'' Hook.
Hybrid names with uncertain taxonomic status
The status of the following hybrids is unresolved:
* ''Ceanothus'' × ''arnoldii'' Dippel
* ''Ceanothus'' × ''burkwoodii'' auct.
* ''Ceanothus'' × ''burtonensis'' Renss.
* ''Ceanothus'' × ''cyam'' L.W.Lenz
* ''Ceanothus'' × ''delilianus'' Spach
* ''Ceanothus'' × ''humboldtensis'' Roof
* ''Ceanothus'' × ''intermedius'' Koehne
* ''Ceanothus'' × ''pallidus'' Koehne
* ''Ceanothus'' × ''pallidus'' Lindl.
* ''Ceanothus'' × ''roseus'' Koehne
Description
Growth pattern
The majority of the species are 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, which ...
, but the handful of species adapted to cold winters are deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
. The leaves are opposite or alternate (depending on species), small (typically 1–5 cm long), simple, and mostly with serrated margins.
Leaves and stems
Ceanothus leaves may be arranged opposite to each other on the stem, or alternate
Alternative or alternate may refer to:
Arts, entertainment and media
* Alternative (''Kamen Rider''), a character in the Japanese TV series ''Kamen Rider Ryuki''
* ''The Alternative'' (film), a 1978 Australian television film
* ''The Alternative ...
. Alternate leaves may have either one or three main veins rising from the base of the leaf.[Native Shrubs of the Sierra Nevada, John Hunter Thomas, Dennis R. Parnell, University of California Press, 1974, p. 70–77]
/ref>
The leaves have a shiny upper surface that feels "gummy" when pinched between the thumb and forefinger, and the roots of most species have red inner root bark.[Edible and Medicinal Plants of the West, Gregory L. Tilford, ]
Flowers and fruit
The flowers are white, greenish–white, blue, dark purple-blue, pale purple or pink, maturing into a dry, three-lobed seed capsule.
The flowers are tiny and fragrant and produced in large, dense clusters. A few species are reported to be so intensely fragrant they are almost nauseating, and are said to resemble the odor of "boiling honey in an enclosed area". The seeds of this plant can lie dormant for hundreds of years, and ''Ceanothus'' species are typically dependent on forest fires to trigger germination of their seeds.[
Fruits are hard, nutlike capsules.][Flowering Plants of the Santa Monica Mountains, Nancy Dale, 2nd Ed., 2000, pp. 166–167]
Distribution
Plants in this genus are widely distributed and can be found on dry, sunny hillsides from coastal scrub lands to open forest clearings, from near sea level to in elevation. These plants are profusely distributed throughout the Rocky Mountains from British Columbia south through Colorado, the Cascades of Oregon and California, and the Coastal Ranges of California.
''Ceanothus velutinus
''Ceanothus velutinus'', with the common names snowbrush ceanothus, red root, and tobacco brush, is a species of shrub in the family Rhamnaceae. It is native to western North America from British Columbia to California to Colorado, where it gro ...
'' is perhaps the most widespread member of this genus, occurring through much of western North America.[ The plants in this genus often co-occur with one another, especially when they are more distantly related.]
Uses
Wildlife
Ceanothus is a good source of nutrition for deer, specifically 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 whit ...
along the West Coast of the United States
The West Coast of the United States, also known as the Pacific Coast, Pacific states, and the western seaboard, is the coastline along which the Western United States meets the North Pacific Ocean. The term typically refers to the contiguous U.S ...
. However, the leaves are not as nutritious from late spring to early fall as they are in early spring. Porcupines and quail have also been seen eating stems and seeds of these shrubs. The leaves are a good source of protein and the stems and leaves have been found to contain a high amount of calcium.
Cultivation
Many ''Ceanothus'' species are popular ornamental plant
Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...
s for gardens. Dozens of hybrids and cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...
s have been selected, such as flexible ceanothus, ''Ceanothus × flexilis'' (''C. cuneatus'' × ''C. prostratus'').
AGM cultivars
The following cultivars
A cultivar is a type of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and when Plant propagation, propagated retain those traits. Methods used to propagate cultivars include: division, root and st ...
and hybrids have gained the Royal Horticultural Society
The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity.
The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...
's Award of Garden Merit
The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions.
History
The Award of Garden Merit ...
():
*’Autumnal Blue’
*'Blue Mound'
*'Burkwoodii'
*'Cascade'
*'Concha'
*'Dark Star'
*'Gloire de Versailles'
*'Mystery Blue'
*'Perle Rose'
*'Puget Blue'
*'Skylark'
*'Topaze'
*'Trewithen Blue'
*''C. thyrsifolius'' var. ''repens''
Other cultivars available include:-
There are also more cultivars and hybrids of ''Ceanothus arboreus
''Ceanothus arboreus'' is a species of perennial shrub to small tree in the family Rhamnaceae, commonly known as the feltleaf ceanothus, island ceanothus, and island mountain lilac. It is the largest member of the California lilacs (the ''Ceanot ...
'', '' Ceanothus griseus horizontalis'' (groundcovers), and ''Ceanothus thyrsiflorus
''Ceanothus thyrsiflorus'', known as blueblossom or blue blossom ceanothus, is an evergreen shrub in the buckthorn family Rhamnaceae that is endemism, endemic to Oregon and California in the US. The term 'Californian lilac' is also applied to thi ...
'' in the nursery trade.
Propagation
Propagation
Propagation can refer to:
* Chain propagation in a chemical reaction mechanism
*Crack propagation, the growth of a crack during the fracture of materials
* Propaganda, non-objective information used to further an agenda
* Reproduction, and other fo ...
of ceanothus is by seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
, following 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 ...
and stratification
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 ...
. Seeds are soaked in water for 12 hours followed by chilling at 1 °C for one to three months. It can also sprout from roots and/or stems. Seeds are stored in plant litter in large quantities. It is estimated that there are about two million seeds per acre in forest habitats. Seeds are dispersed propulsively from capsules and, it has been estimated, can remain viable for hundreds of years. In habitat, the seeds of plants in this genus germinate only in response to range fires and forest fires.
Other uses
Native Americans used the dried leaves of this plant as an herbal tea, and early pioneers used the plant as a substitute for black tea. Miwok
The Miwok (also spelled Miwuk, Mi-Wuk, or Me-Wuk) are members of four linguistically related Native American groups indigenous to what is now Northern California, who traditionally spoke one of the Miwok languages in the Utian family. The word ...
Indians of California made baskets from Ceanothus branches. ''Ceanothus integerrimus'' has been used by North American tribes to ease childbirth.
Nitrogen fixation
''Ceanothus'' is actinorhizal Actinorhizal plants are a group of angiosperms characterized by their ability to form a symbiosis with the nitrogen fixing actinomycetota ''Frankia''. This association leads to the formation of nitrogen-fixing root nodules.
Classification
Actinorh ...
, meaning it fixes nitrogen through a symbiotic relationship with ''Frankia
''Frankia'' is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the ''Rhizobium'' bacteria found in the root nodules of legumes in the family Fabaceae. ''Frankia'' also initiate the forming of root ...
.'' Six genera within Rhamnaceae are actinorhizal, but ''Ceanothus'' is the only genus not in the monophyletic tribe Colletieae. This suggests that actinorhizal symbiosis may have evolved twice in Rhamnaceae. ''Frankia
''Frankia'' is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the ''Rhizobium'' bacteria found in the root nodules of legumes in the family Fabaceae. ''Frankia'' also initiate the forming of root ...
'' forms nodules on the roots of ''Ceanothus'', converting atmospheric nitrogen () into ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...
() using nitrogenase
Nitrogenases are enzymes () that are produced by certain bacteria, such as cyanobacteria (blue-green bacteria) and rhizobacteria. These enzymes are responsible for the Organic redox reaction, reduction of nitrogen (N2) to ammonia (NH3). Nitrog ...
.
References
{{Taxonbar, from=Q311139
Rhamnaceae genera
Flora of North America
Taxa named by Carl Linnaeus
Garden plants of North America
Drought-tolerant plants
Saponaceous plants
Flora of California