Cornus

Cornus is a genus of about 30–60 species[Note 1] of woody plants in the family Cornaceae, commonly known as dogwoods, which can generally be distinguished by their blossoms, berries, and distinctive bark.[3] Most are deciduous trees or shrubs, but a few species are nearly herbaceous perennial subshrubs, and a few of the woody species are evergreen. Several species have small heads of inconspicuous flowers surrounded by an involucre of large, typically white petal-like bracts, while others have more open clusters of petal-bearing flowers. The various species of dogwood are native throughout much of temperate and boreal Eurasia and North America, with China, Japan, and the southeastern United States being particularly rich in native species.

For other uses, see Cornus (disambiguation).
"Dogwood" redirects here. For other uses, see Dogwood (disambiguation).

Cornus
Temporal range: Late Campanian–Holocene, 73–0 Ma[1]
Cornus kousa var. chinensis
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Cornales
Family: Cornaceae
Genus: Cornus
L.
Type species
Cornus mas
Subgenera
  • Afrocrania
  • Arctocrania
  • Cornus
  • Cynoxylon
  • Discocrania
  • Kraniopsis
  • Mesomora
  • Sinocornus
  • Syncarpea
  • Yinquania
In species such as this Cornus × unalaschkensis, the tiny four-petaled flowers are clustered in a tightly packed, flattened cyme at the center of four showy white petal-like bracts.
Cornus mas
Cornus florida in spring
Cornus drummondii in flower
Mature and immature flowers of Cornus canadensis, Bonnechere Provincial Park, Ontario
Cornus canadensis fruit
Spring budding

Species include the common dogwood Cornus sanguinea of Eurasia, the widely cultivated flowering dogwood (Cornus florida) of eastern North America, the Pacific dogwood Cornus nuttallii of western North America, the Kousa dogwood Cornus kousa of eastern Asia, and two low-growing boreal species, the Canadian and Eurasian dwarf cornels (or bunchberries), Cornus canadensis and Cornus suecica respectively.

Depending on botanical interpretation, the dogwoods are variously divided into one to nine genera or subgenera; a broadly inclusive genus Cornus is accepted here.

Terminology

The name "dog-tree" entered the English vocabulary before 1548, becoming "dogwood" by 1614. Once the name dogwood was affixed to this kind of tree, it soon acquired a secondary name as the Hound's Tree, while the fruits came to be known as "dogberries" or "houndberries" (the latter a name also for the berries of black nightshade, alluding to Hecate's hounds). Another theory advances the view that "dogwood" was derived from the Old English dagwood (dagwood is a form which is unattested), from the use of the slender stems of its very hard wood for making sharp objects:[4] "dags" (daggers, skewers, and arrows).[5][6] Another, earlier name of the dogwood in English, is the "whipple-tree". Geoffrey Chaucer uses "whippletree" in The Canterbury Tales ("The Knight's Tale", verse 2065) to refer to the dogwood. A whippletree is also an element of the traction of a horse-drawn cart, linking the drawpole of the cart to the harnesses of the horses in file; these items still bear the name of the tree from which they are commonly carved.

Cherokee princess dogwood

Characteristics

Dogwoods have simple, untoothed leaves with the veins curving distinctively as they approach the leaf margins. Most dogwood species have opposite leaves, while a few, such as Cornus alternifolia and C. controversa, have their leaves alternate. Dogwood flowers have four parts. In many species, the flowers are borne separately in open (but often dense) clusters, while in various other species (such as the flowering dogwood), the flowers themselves are tightly clustered, lacking showy petals, but surrounded by four to six large, typically white petal-like bracts.

The fruits of all dogwood species are drupes with one or two seeds, often brightly colorful. The drupes of species in the subgenera Cornus are edible. Many are without much flavor. Cornus kousa and Cornus mas are sold commercially as edible fruit trees. The fruits of Cornus kousa have a sweet, tropical pudding like flavor in addition to hard pits. The fruits of Cornus mas are both tart and sweet when completely ripe. They have been eaten in Eastern Europe for centuries, both as food and medicine to fight colds and flus. They are very high in vitamin C. However, those of species in subgenus Swida are mildly toxic to people, though readily eaten by birds.

Dogwoods are used as food plants by the larvae of some species of butterflies and moths, including the emperor moth, the engrailed, the small angle shades, and the following case-bearers of the genus Coleophora: C. ahenella, C. salicivorella (recorded on Cornus canadensis), C. albiantennaella, C. cornella and C. cornivorella, with the latter three all feeding exclusively on Cornus.

Uses

Dogwoods are widely planted horticulturally, and the dense wood of the larger-stemmed species is valued for certain specialized purposes. Cutting boards and other fine turnings can be made from this fine grained and beautiful wood. Over 32 different varieties of game birds, including quail, feed on the red seeds.[7]

Horticulture

Various species of Cornus, particularly the flowering dogwood (Cornus florida), are ubiquitous in American gardens and landscaping; horticulturist Donald Wyman stated, "There is a dogwood for almost every part of the U.S. except the hottest and driest areas".[8] In contrast, in England the lack of sharp winters and hot summers makes Cornus florida very shy of flowering.[9]

Other Cornus species are stoloniferous shrubs that grow naturally in wet habitats and along waterways. Several of these are used along highways and in naturalizing landscape plantings, especially those species with bright red or bright yellow stems, particularly conspicuous in winter, such as Cornus stolonifera.

The following cultivars, of mixed or uncertain origin, have gained the Royal Horticultural Society’s Award of Garden Merit (confirmed 2017):[10]

  • ‘Eddie’s White Wonder’[11]
  • ‘Norman Hadden’[12]
  • ‘Ormonde’[13]
  • ‘Porlock’[14]

Fruits

The species Cornus mas is commonly cultivated in southeastern Europe for its showy, edible berries, that have the color of the carnelian gemstone. Cornelian-cherries have one seed each and are used in syrups and preserves.[15]

Wood

Dense and fine-grained, dogwood timber has a density of 0.79 and is highly prized for making loom shuttles, tool handles, roller skates and other small items that require a very hard and strong wood.[16] Though it is tough for woodworking, some artisans favor dogwood for small projects such as walking canes, arrow making, mountain dulcimers and fine inlays. Dogwood wood is an excellent substitute for persimmon wood in the heads of certain golf clubs ("woods"). Dogwood lumber is rare in that it is not readily available with any manufacturer and must be cut down by the person(s) wanting to use it.

Larger items have also been occasionally made of dogwood, such as the screw-in basket-style wine or fruit presses. The first kinds of laminated tennis rackets were also made from this wood, cut into thin strips.

Dogwood twigs were used by U.S. pioneers to brush their teeth. They would peel off the bark, bite the twig and then scrub their teeth.[17]

Traditional medicine

The bark of Cornus species is rich in tannins and has been used in traditional medicine as a substitute for quinine.[18] During the American civil war confederate soldiers would make a tea from the bark to treat pain and fevers, and dogwood leaves in a poultice to cover wounds.[19]

The Japanese cornel, C. officinalis, is used extensively in traditional Chinese medicine as shān zhū yú for several minor ailments.[20]

Classification

The following classification recognizes a single, inclusive genus Cornus,[21][22] with four subgroups and ten subgenera supported by molecular phylogeny.[23][24][25] Geographical ranges as native plants are given below. In addition, cultivated species occasionally persist or spread from plantings beyond their native ranges, but are rarely if ever locally invasive.

Blue- or white-fruited dogwoods

Paniculate or corymbose cymes; bracts minute, nonmodified; fruits globose or subglobose, white, blue, or black:

Cornelian cherries

Umbellate cymes; bracts modified, non-petaloid; fruits oblong, red; stone walls filled with cavities:

Big-bracted dogwoods

Capitular cymes:

  • Subgenus Discocrania. Bracts 4, modified, non-petaloid; fruits oblong, red.
    • Cornus disciflora.
  • Subgenus Cynoxylon. Bracts 4 or 6, large and petaloid, fruits oblong, red.
  • Subgenus Syncarpea. Bracts 4, large and petaloid, fruits red, fused into a compound multi-stoned berry.

Dwarf dogwoods

Minute corymbose cymes; bracts 4, petaloid; fruit globose, red; rhizomatous herb:

Incertae sedis (unplaced)

Horticultural hybrids

Cornus × rutgersensis (Hybrid: C. florida × C. kousa). Horticulturally developed.[30]

Cultural references

The inflorescence of the Pacific dogwood (Cornus nuttallii) is the official flower of the province of British Columbia. The flowering dogwood (Cornus florida) and its inflorescence are the state tree and the state flower respectively for the U.S. Commonwealth of Virginia. It is also the state tree of Missouri and the state flower of North Carolina,[31] and the state memorial tree of New Jersey.[32]

The poet Virgil makes reference to a haunted copse of cornel and myrtle in Book III of the Aeneid. The hero Aeneas attempts to break off boughs to decorate an altar, but instead the wood drips with black blood.[33] Anne Morrow Lindbergh gives a vivid description of the dogwood tree in her poem "Dogwood".[34]

A Christian legend of unknown origin proclaims that the cross used to crucify Jesus was constructed of dogwood.[35] As the story goes, during the time of Jesus, the dogwood was larger and stronger than it is today and was the largest tree in the area of Jerusalem. After his crucifixion, Jesus changed the plant to its current form: he shortened it and twisted its branches to ensure an end to its use for the construction of crosses.[36] He also transformed its inflorescence into a representation of the crucifixion itself, with the four white bracts cross-shaped representing the four corners of the cross, each bearing a rusty indentation as of a nail, the red stamens of the flower representing Jesus' crown of thorns, and the clustered red fruit representing his blood.[37][38]

In the Victorian era, flowers or sprigs of dogwood were presented to unmarried women by male suitors to signify affection. The returning of the flower conveyed indifference on the part of the woman; if she kept it, it became a sign of mutual interest.

The term "dogwood winter", in colloquial use in the American Southeast, is sometimes used to describe a cold snap in spring, presumably because farmers believed it was not safe to plant their crops until after the dogwoods blossomed.[39]

"When the dogwoods start to bloom" is the opening line of the country song "Six Feet Apart" by Luke Combs

Etymology

Cornus is the ancient Latin word for the Cornelian cherry, Cornus mas. ‘Cornus’ means ‘horn’.[40]

Notes
  1. 58 species according to Xiang et al. (2006)[2]
  2. Cornus sericea, treated separately here, is sometimes included in a more broadly taken concept of Cornus alba, which in that sense is also native in North America.
  3. Cornus obliqua, here recognized separately, has been included in a broader concept of C. amomum by some botanists. Canadian reports for C. amomum are apparently all based on plants here classified as C. obliqua.
  4. Cornus obliqua is sometimes included in a more broadly taken concept of C. amomum, also in the eastern U.S.
  5. Cornus sericea (including C. stolonifera) is sometimes itself included in a more broadly taken concept of the otherwise Eurasian Cornus alba.

References
  1. Atkinson, Brian A.; Stockey, Ruth A.; Rothwell, Gar W. (2016). "Cretaceous origin of dogwoods: an anatomically preserved Cornus (Cornaceae) fruit from the Campanian of Vancouver Island". PeerJ. 4: e2808. doi:10.7717/peerj.2808. PMC 5180587. PMID 28028474.
  2. Qiu-Yun (Jenny) Xiang; David T. Thomas; Wenheng Zhang; Steven R. Manchester & Zack Murrell (2006). "Species level phylogeny of the genus Cornus (Cornaceae) based on molecular and morphological evidence – implications for taxonomy and Tertiary intercontinental migration". Taxon. 55 (1): 9–30. doi:10.2307/25065525. JSTOR 25065525.
  3. "Notable Characteristics of Dogwood Trees". answers.com. Archived from the original on August 26, 2014. Retrieved August 24, 2014.
  4. "dogwood". Online Etymology Dictionary. Douglas Harper.
  5. Vedel, H., & Lange, J. (1960). Trees and Bushes in Wood and Hedgerow. Metheun & Co. Ltd., London.
  6. Fernald, Merritt Lyndon (1950). Gray's Manual of Botany (8th ed.). New York: American Book Company.
  7. "Wildlife Dogwood Trees". Prepper Gardens. Archived from the original on 2013-11-16. Retrieved January 8, 2013.
  8. Wyman's Garden Encyclopedia, s.v. "Cornus"
  9. Alice M. Coats, Garden Shrubs and their Histories (1964) 1992, s.v. "Cornus".
  10. "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 16. Retrieved 24 January 2018.
  11. "RHS Plantfinder - Cornus 'Eddie's White Wonder'". Retrieved 2 February 2018.
  12. "RHS Plantfinder - Cornus 'Norman Hadden'". Retrieved 2 February 2018.
  13. "RHS Plantfinder - Cornus 'Ormonde'". Retrieved 2 February 2018.
  14. "RHS Plantfinder - Cornus 'Porlock'". Retrieved 2 February 2018.
  15. "Cornus mas - Plant Finder". www.missouribotanicalgarden.org.
  16. "Dogwood." McGraw-Hill Concise Encyclopedia of Science and Technology. New York: McGraw-Hill, 2006. Credo Reference. Web. 17 September 2012.
  17. Gunn, John C. (1835). Gunn's Domestic Medicine (4th ed.). John M. Gallagher, printer. p. 523.
  18. "Dogwood or cornel." The Columbia Encyclopedia. New York: Columbia University Press, 2008. Credo Reference. Web. 17 September 2012.
  19. "Medicinal Dogwood Trees". Prepper Gardens. Archived from the original on 2013-11-16. Retrieved January 8, 2013.
  20. Schafer, Peg (2011). The Chinese Medicinal Herb Farm: A Cultivator's Guide to Small-scale Organic Herb Production. Chelsea Green Publishing. pp. 312 (page 150). ISBN 9781603583305.
  21. Richard H. Eyde (1987). "The case for keeping Cornus in the broad Linnaean sense". Systematic Botany. 12 (4): 505–518. doi:10.2307/2418886. JSTOR 2418886.
  22. Richard H. Eyde (1988). "Comprehending Cornus: puzzles and progress in the systematics of the dogwoods". Botanical Review. 54 (3): 233–351. doi:10.1007/bf02868985. JSTOR 4354115. S2CID 12507834.
  23. Fan, Chuanzhu; Xiang, Qiu-Yun (2001). "Phylogenetic relationships within Cornus (Cornaceae) based on 26S rDNA sequences". American Journal of Botany. 88 (6): 1131–1138. doi:10.2307/2657096. JSTOR 2657096. PMID 11410478.
  24. Zhiang, Qiu-Yun; Thomas, David T.; Zhang, Wenheng; Manchester, Steven R.; Murrell, Zack (2006). "Species level phylogeny of the genus Cornus (Cornaceae) based on molecular and morphological evidence—implications for taxonomy and Tertiary intercontinental migration". Taxon. 55 (1). Retrieved 29 January 2016.
  25. Nowicki, Marcin; Boggess, Sarah L.; Saxton, Arnold M.; Hadziabdic, Denita; Xiang, Qiu-Yun Jenny; Molnar, Thomas; Huff, Matthew L.; Staton, Margaret E.; Zhao, Yichen (2018-10-23). Heinze, Berthold (ed.). "Haplotyping of Cornus florida and C. kousa chloroplasts: Insights into species-level differences and patterns of plastic DNA variation in cultivars". PLOS ONE. 13 (10): e0205407. Bibcode:2018PLoSO..1305407N. doi:10.1371/journal.pone.0205407. ISSN 1932-6203. PMC 6198962. PMID 30352068.
  26. "Tropicos | Name - Cornus peruviana J.F. Macbr". www.tropicos.org. Retrieved 2016-01-29.
  27. Macbride, J.F. (1959). "Cornaceae". Flora of Peru. 13 pt.5 no.1. Field Museum. pp. 44–45.
  28. Manchester, S.R.; Xiang, X-P.; Xiang, Q-Y (2010). "Fruits of Cornelian Cherries (Cornaceae: Cornus Subg. Cornus) in the Paleocene and Eocene of the Northern Hemisphere" (PDF). International Journal of Plant Sciences. 171 (8): 882–891. doi:10.1086/655771. S2CID 83524109.
  29. Manchester, S.R. (1994). "Fruits and Seeds of the Middle Eocene Nut Beds Flora, Clarno Formation, Oregon". Palaeontographica Americana. 58: 30–31.
  30. "Cornus florida × Cornus kousa". Landscape Plants: Images, identification, and information. Oregon State University. Retrieved 20 May 2011.
  31. "Find Official State Flower for USA | Teleflora". www.teleflora.com.
  32. "List of State Trees | State Symbols USA". statesymbolsusa.org.
  33. Aeneid III 22-23: Forte fuit iuxta tumulus, quo cornea summo virgulta et densis hastilibus horrida myrtus.
  34. Morrow, Anne (1956). Dogwood. 333 6th Avenue, New York 14, N.Y.: Pantheon Books. pp. 38–39.CS1 maint: location (link)
  35. "The Old Legend of the Dogwood". www.footprint.co.za. Archived from the original on September 28, 2007.
  36. Jeffrey G. Meyer (2004). The Tree Book: A Practical Guide to Selecting and Maintaining the Best Trees for Your Yard and Garden. Simon and Schuster. pp. 258–. ISBN 978-0-7432-4974-4.
  37. Thomas E. Barden (1991). Virginia Folk Legends. University of Virginia Press. pp. 61–. ISBN 978-0-8139-1335-3.
  38. Ronald L. Baker (1 August 1984). Hoosier Folk Legends. Indiana University Press. pp. 7–. ISBN 0-253-20334-1.
  39. "Archived copy". Archived from the original on 2011-05-03. Retrieved 2011-05-20.CS1 maint: archived copy as title (link)
  40. Gledhill, David (2008). "The Names of Plants". Cambridge University Press. ISBN 9780521866453 (hardback), ISBN 9780521685535 (paperback). pp 121
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