In this article we are going to explore in depth Ceanothus and its impact on our society. Ceanothus is a topic that has generated great interest in recent years, sparking intense debates and reflections in various areas. Throughout history, Ceanothus has been a determining factor in people's lives, influencing the way they think, act and relate to their environment. In this sense, it is crucial to understand the importance of Ceanothus today, as well as the implications it has on our daily lives. Through this article, we aim to shed light on this topic and analyze its different facets, in order to contribute to a better understanding and approach to Ceanothus in the current context.
The genus is native to North America 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 0.5–3 metres (1.6–9.8 ft) tall, but C. arboreus and C. thyrsiflorus, both native to California, can be small multi-trunked trees up to 6–7 metres (20–23 ft) 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.
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 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.
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 [citation needed] 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.
Leaves and stems
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.
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.
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".[citation needed] The seeds of this plant can lie dormant for hundreds of years,[citation needed] and Ceanothus species are typically dependent on forest fires to trigger germination of their seeds.
Fruits are hard, nutlike capsules.
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 9,000 feet (2,700 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.
Uses
Wildlife
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.
Cultivation
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]
Royal Horticultural Society's Award of Garden Merit cultivars
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]
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 Indians of California make baskets from Ceanothus branches. Ceanothus integerrimus has been used by North American tribes to ease childbirth.
Nitrogen fixation
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.Frankia forms nodules on the roots of Ceanothus, converting atmospheric nitrogen (N 2) into ammonia (NH 3) using nitrogenase.
References
^"Genus: Ceanothus L."Germplasm Resources Information Network. United States Department of Agriculture. 2004-02-10. Archived from the original on 2009-01-14. Retrieved 2012-04-25.
^ abcd"Ceanothus L."Plants of the World Online. Royal Botanical Gardens Kew. Retrieved 2 December 2023.
^USDA, NRCS (n.d.). "Ceanothus". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 29 September 2019.
^
Coladonato, Milo (1993). "Ceanothus americanus". Fire Effects Information System (online). Rocky Mountain Research Station, Fire Sciences Laboratory (Producer): U.S.D.A; Forest Service. Retrieved March 3, 2016.