ceanothus

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.

{{cite web

|url=http://www.fs.fed.us/database/feis/plants/shrub/ceaame/all.html

|title=Ceanothus americanus

|author=Coladonato, Milo

|year=1993

|work=Fire Effects Information System (online)

|publisher=U.S.D.A; Forest Service

|location=Rocky Mountain Research Station, Fire Sciences Laboratory (Producer)

|access-date=March 3, 2016

}} 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.

File:Ceanothus cuneatus1.jpg (buck brush) in Pinnacles National Park]]

{{As of|December 2023}}, accepted species are:{{cite web | url = http://www.theplantlist.org/1.1/browse/A/Rhamnaceae/Ceanothus/ | title = The Plant List entry for Myrica | date = September 2013 | website = The Plant List, v.1.1 | publisher = Royal Botanic Gardens, Kew and the Missouri Botanical Garden | access-date = 15 December 2020}}

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• Ceanothus americanus L. – New Jersey tea; red root[http://wisplants.uwsp.edu/scripts/detail.asp?spcode=CEAAME University of Wisconsin–Stevens Point Plant Database: Ceanothus americanus] {{webarchive|url=https://web.archive.org/web/20070116012715/http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=CEAAME |date=2007-01-16 }}
• Ceanothus arboreus Greene – feltleaf ceanothus
• Ceanothus arcuatus McMinn
• Ceanothus × bakeri {{small|Greene ex McMinn}}
• Ceanothus bolensis S.Boyd & J.E.Keeley
• Ceanothus buxifolius Willd. ex Schult. & Schult.f.
• Ceanothus caeruleus Lag
• Ceanothus confusus J.T. Howell – Rincon Ridge ceanothus
• Ceanothus × connivens Greene – trailing buckbrush
• Ceanothus cordulatus Kellogg – whitethorn ceanothus
• Ceanothus crassifolius Torr. – hoaryleaf ceanothus
• Ceanothus cuneatus (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 Eastw. – San Diego buckbrush
• Ceanothus decornutus V.T.Parker
• Ceanothus dentatus Torr. & A.Gray – sandscrub ceanothus
• Ceanothus depressus Benth. – junco
• Ceanothus divergens Parry – Calistoga ceanothus
• Ceanothus diversifolius Kellogg – pinemat
• Ceanothus fendleri A.Gray – Fendler's ceanothus
• Ceanothus fernandezii {{small|Villarreal, A.E.Estrada & Encina}}
• 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 Hoover & J.B.Roof – Hearst Ranch buckbrush
• Ceanothus herbaceus Raf. – Jersey tea
• Ceanothus × humboldtensis {{small|Roof}}
• Ceanothus impressus Trel. – Santa Barbara ceanothus
• Ceanothus incanus Torr. & A.Gray – coast whitethorn
• Ceanothus integerrimus Hook. & Arn. – deerbrush ceanothus
• Ceanothus jepsonii Greene – Jepson ceanothus
• subsp. albiflorus (Howell) C.L.Schmidt
• subsp. jepsonii Greene
• Ceanothus lemmonii Parry – Lemmon's ceanothus
• Ceanothus leucodermis Greene – chaparral whitethorn
• Ceanothus × lobbianus {{small|Hook.}}
• Ceanothus × lorenzenii {{small|(Jeps.) McMinn}}
• Ceanothus maritimus Hoover – maritime ceanothus
• Ceanothus martini 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 × mendocinensis {{small|McMinn}}
• 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 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 Coville – Coville ceanothus
• Ceanothus prostratus 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 × regius {{small|(Jeps.) McMinn}}
• Ceanothus roderickii Knight – Pine Hill buckbrush
• Ceanothus × rugosus {{small|Greene}}
• Ceanothus sanguineus Pursh – redstem ceanothus
• Ceanothus serpyllifolius Nutt. – Coastal Plain buckbrush
• Ceanothus × serrulatus {{small|McMinn}}
• Ceanothus sonomensis J.T. Howell – Sonoma ceanothus
• Ceanothus spinosus Nutt. – green bark ceanothus
• Ceanothus thyrsiflorus Eschsch. – blueblossom
• Ceanothus tomentosus Parry – woolyleaf ceanothus
• Ceanothus × veitchianus {{small|Hook.}}
• Ceanothus velutinus Dougl. ex Hook. – snowbrush ceanothus
• subsp. laevigatus (Torr. & A.Gray) Piper & Beattie
• subsp. velutinus Dougl. ex Hook.
• Ceanothus verrucosus Nutt. – Barranca brush

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The status of the following species is unresolved:

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• 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 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.

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The following hybrids have been described:

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• 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.

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The status of the following hybrids is unresolved:

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• 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

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Image:Ceanothus arboreus 2.jpg, illustrating the three basal leaf veins characteristic of this genus]]

The majority {{citation needed|date=June 2014}} of the species are evergreen, but the handful of species adapted to cold winters are deciduous. The leaves are opposite or alternate (depending on species), small (typically 1–5 cm long), simple, and mostly with serrated margins.

Ceanothus leaves may be arranged opposite to each other on the stem, or alternate. 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, [https://books.google.com/books?id=RgUUOn9Fx2wC&dq=ceanothus+one+vein&pg=PA74]

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, {{ISBN|0-87842-359-1}}

Image:Ceanothus fendleri flower1.jpg blossom]]

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".{{citation needed|date=October 2021}} The seeds of this plant can lie dormant for hundreds of years,{{citation needed|date=June 2014}} 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

Image:Ceanothus.jpg

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 {{convert|9000|ft|m}} 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 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.{{cite journal|last1=Ackerly|first1=D. D.|last2=Schwilk|first2=D. W.|last3=Webb|first3=C. O.|title=Niche evolution and adaptive radiation: Testing the order of trait divergence|journal=Ecology|volume=87|issue=sp7|year=2006|pages=S50–S61|issn=0012-9658|doi=10.1890/0012-9658(2006)87[50:NEAART]2.0.CO;2|pmid=16922302}}

File:Ceanothus integerrimus 01.jpg (deerbrush) in Yosemite National Park]]

Ceanothus is a good source of nutrition for deer, specifically mule deer along the West Coast of the United States. 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.

Many Ceanothus species are popular ornamental plants for gardens. Dozens of hybrids and cultivars have been selected, such as flexible ceanothus, Ceanothus × flexilis (C. cuneatus × C. prostratus).{{citation needed|date=January 2018}}

The following cultivars and hybrids have gained the Royal Horticultural Society's Award of Garden Merit ({{as of|2017|lc=y}}):{{cite web |url=https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf |title=AGM Plants - Ornamental |date=July 2017 |page=16 |publisher=Royal Horticultural Society |access-date=24 January 2018}}

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• ’Autumnal Blue’{{cite web

|url=https://www.rhs.org.uk/Plants/91791/i-Ceanothus-i-Autumnal-Blue/Details

|title=RHS Plantfinder - Ceanothus 'Autumnal Blue'

|publisher=Royal Horticultural Society |access-date=21 January 2018}}

• 'Blue Mound'{{cite web|title=RHS Plant Selector - Ceanothus 'Blue Mound'|url=https://www.rhs.org.uk/Plants/63246/Ceanothus-Blue-Mound/Details | access-date=15 April 2020}}
• 'Burkwoodii'{{cite web|title=RHS Plant Selector - Ceanothus 'Burkwoodii'|url=https://www.rhs.org.uk/Plants/96855/Ceanothus-Burkwoodii/Details | access-date=15 April 2020}}
• 'Cascade'{{cite web|title=RHS Plant Selector - Ceanothus 'Cascade'|url=https://www.rhs.org.uk/Plants/91792/Ceanothus-Cascade/Details | access-date=15 April 2020}}
• 'Concha'{{cite web | url = https://www.rhs.org.uk/Plants/97563/Ceanothus-Concha/Details

| title = Ceanothus 'Concha' | publisher = RHS | access-date = 12 April 2020}}

• 'Dark Star'{{cite web | url = https://www.rhs.org.uk/Plants/95793/Ceanothus-Dark-Star/Details

| title = Ceanothus 'Dark Star' | publisher = RHS | access-date = 12 April 2020}}

• 'Gloire de Versailles'{{cite web | url = https://www.rhs.org.uk/Plants/69338/Ceanothus-x-delileanus-Gloire-de-Versailles/Details

| title = Ceanothus × delileanus 'Gloire de Versailles' | publisher = RHS | access-date = 12 April 2020}}

• 'Mystery Blue'{{cite web | url = https://www.rhs.org.uk/Plants/274981/Ceanothus-thyrsiflorus-Mystery-Blue/Details

| title = Ceanothus thyrsifolius 'Mystery Blue' | publisher = RHS | access-date = 12 April 2020}}

• 'Perle Rose'{{cite web | url = https://www.rhs.org.uk/Plants/52985/Ceanothus-x-pallidus-Perle-Rose/Details

| title = Ceanothus × pallidus 'Perle Rose' | publisher = RHS | access-date = 12 April 2020}}

• 'Puget Blue'{{cite web | url = https://www.rhs.org.uk/Plants/95971/Ceanothus-Puget-Blue/Details

| title = Ceanothus 'Puget Blue' | publisher = RHS | access-date = 12 April 2020}}

• 'Skylark'{{cite web | url = https://www.rhs.org.uk/Plants/236885/Ceanothus-Skylark/Details

| title = Ceanothus 'Skylark' | publisher = RHS | access-date = 12 April 2020}}

• 'Topaze'{{cite web | url = https://www.rhs.org.uk/Plants/46202/Ceanothus-x-delileanus-Topaze/Details

| title = Ceanothus × delineanus 'Topaze' | publisher = RHS | access-date = 12 April 2020}}

• 'Trewithen Blue'{{cite web | url = https://www.rhs.org.uk/Plants/3253/Ceanothus-arboreus-Trewithen-Blue/Details

| title = Ceanothus arboreus 'Trewithen Blue' | publisher = RHS | access-date = 12 April 2020}}

• C. thyrsifolius var. repens {{cite web | url = https://www.rhs.org.uk/Plants/94754/Ceanothus-thyrsiflorus-var-repens/Details

| title = Ceanothus thyrsifolius var. repens | publisher = RHS | access-date = 12 April 2020}}

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Other cultivars available include:-

There are also more cultivars and hybrids of Ceanothus arboreus, Ceanothus griseus horizontalis (groundcovers), and Ceanothus thyrsiflorus in the nursery trade.

Propagation of ceanothus is by seed, following scarification and stratification. 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. {{Citation needed|date=December 2013}}

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 Indians of California make baskets from Ceanothus branches. Ceanothus integerrimus has been used by North American tribes to ease childbirth.Moerman, D. (1988). Native American Ethnobotany. Timber Press, Oregon.

Ceanothus is actinorhizal, meaning it fixes nitrogen through a symbiotic relationship with Frankia. 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.{{Cite web|last=Vining|first=Susan|date=2020-02-26|title=Rhamnaceae {{!}} Frankia|url=https://frankia.mcb.uconn.edu/home/rhamnaceae/|access-date=2021-06-12|language=en-US}} Frankia forms nodules on the roots of Ceanothus, converting atmospheric nitrogen ({{chem|N|2}}) into ammonia ({{chem|NH|3}}) using nitrogenase.{{Cite web|last=Vining|first=Susan|date=2020-02-26|title=Nodules {{!}} Frankia|url=https://frankia.mcb.uconn.edu/home/nolules/|access-date=2021-06-12|language=en-US}}{{Cite web|last=Vining|first=Susan|date=2020-02-26|title=Nitrogen Fixation {{!}} Frankia|url=https://frankia.mcb.uconn.edu/frankia-biology/nitrogen-fixation/|access-date=2021-06-12|language=en-US}}

{{Reflist|refs=

{{cite web |title=Largest Genera in Continental North America |url=http://bonap.org/2015_SpecialtyMaps/Most%20Number%20of%20Native%20Species/Native%20Species%20per%20Genus.html |website=BONAP |access-date=29 September 2019}}

[http://www.calflora.org/cgi-bin/specieslist.cgi?where-genus=Ceanothus Calflora Database: Index of Ceanothus species native to California]

{{cite web |title=Ceanothus L. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30006383-2 |website=Plants of the World Online |publisher=Royal Botanical Gardens Kew |access-date=2 December 2023}}

{{PLANTS |id=CEANO |taxon=Ceanothus |access-date=29 September 2019}}

McMahan, L. R. [https://extension.oregonstate.edu/sites/default/files/documents/1/waterwise-plant-profiles.pdf WaterWise Plant Profiles]. Oregon State University Extension Service.

}}

{{Taxonbar|from=Q311139}}

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Category:Rhamnaceae genera

Category:Flora of Northern America

Category:Taxa named by Carl Linnaeus

Category:Garden plants of North America

Category:Drought-tolerant plants

Category:Saponaceous plants

Category:Flora of California