Daphne (plant)

Daphne (/ˈdæfniː/;[2] Greek: Δάφνη, meaning "laurel") is a genus of between 70 and 95 species of deciduous and evergreen shrubs in the family Thymelaeaceae, native to Asia, Europe and north Africa. They are noted for their scented flowers and often brightly coloured berries. Two species are used to make paper. Many species are grown in gardens as ornamental plants; the smaller species are often used in rock gardens. All parts of daphnes are poisonous, especially the berries.

Daphne
Daphne pontica in flower
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Malvales
Family: Thymelaeaceae
Subfamily: Thymelaeoideae
Genus: Daphne
L.[1]
Species

See text.

Description

Daphne species are shrubs, with upright or prostrate stems. Upright species may grow to 1.5 m (5 ft). Their leaves are undivided, mostly arranged alternately (although opposite in D. genkwa), and have short petioles (stalks). The leaves tend to be clustered towards the end of the stems and are of different shapes, although always longer than wide. The leaf surface may be smooth (glabrous) or hairy.[3][4][5]

Many species flower in late winter or very early spring. The flowers are grouped into clusters (inflorescences), either in the leaf axils towards the end of the stems or forming terminal heads. The inflorescences lack bracts. Individual flowers completely lack petals and are formed by four (rarely five) petaloid sepals, tubular at the base with free lobes at the apex. They range in colour from white, greenish yellow or yellow to bright pink and purple. Most of the evergreen species have greenish flowers, while the deciduous species tend to have pink flowers. There are twice the number of stamens as sepals, usually eight, arranged in two series. Stamens either have short filaments or lack filaments altogether and are usually held inside the sepal tube. The style is short or absent, and the stigma is head-shaped (capitate).[3][4][5]

The ovary has a single chamber (locule). The fruits are one-seeded, and are either fleshy berries or dry and leathery (drupaceous[5]). When ripe the fruit is usually red or yellow, sometimes black.[3][4]

Taxonomy

The genus Daphne was first described by Carl Linnaeus in 1753 in Species Plantarum.[1] Linnaeus recognized 10 species, including Daphne mezereum, Daphne laureola and Daphne cneorum.[6] Some of his species are now placed in other related genera (e.g. Linnaeus's Daphne thymelaea is now Thymelaea sanamunda).[7] The number of species in the genus varies considerably between different authorities. The Flora of China states there are about 95 species, 41 of which are endemic to China. Some of these species were reduced to subspecies or varieties by Josef Halda in a series of papers from 1997 onwards,[8] culminating in a monograph on the genus.[9] Version 1.1 of The Plant List accepts 83 species.[10] The Flora of North America states there are 70 species.[5]

Phylogeny and generic limits

A 2002 study based on chloroplast DNA placed Daphne in a group of related genera; however there was only one species representing each genus.[11]

 
 

Edgeworthia

 
 
 
 

Wikstroemia

 
 

Stellera

 
 
 
 

Diarthron

 
 
 

Thymelaea

 
 

Daphne

 
 
 
 
 

A further study published in 2009 included an extra species of Wikstroemia and suggested that this genus was paraphyletic with respect to Stellera, but otherwise agreed with the cladogram above.[12] The distinction between Wikstroemia and Daphne is difficult to make; Halda included Wikstroemia within Daphne.[4] The cladogram shown above suggests that other genera would need to be included as well to make Daphne monophyletic.

Species

The Plant List (version 1.1, September 2013) recognizes the following species:[10]

  • Daphne acutiloba Rehder
  • Daphne alpina L.
  • Daphne altaica Pall.
  • Daphne arbuscula Čelak.
  • Daphne arisanensis Hayata
  • Daphne aurantiaca Diels
  • Daphne axillaris (Merr. & Chun) Chun & C.F.Wei
  • Daphne bholua Buch.-Ham. ex D.Don
  • Daphne blagayana Freyer
  • Daphne brevituba H.F.Zhou ex C.Y.Chang
  • Daphne caucasica Pall.
  • Daphne championii Benth.
  • Daphne chingshuishaniana S.S.Ying
  • Daphne cneorum L.
  • Daphne depauperata H.F.Zhou ex C.Y.Chang
  • Daphne domini Halda
  • Daphne erosiloba C.Y.Chang
  • Daphne esquirolii H.Lév.
  • Daphne feddei H.Lév.
  • Daphne formosana (Hayata) S.S.Ying
  • Daphne gemmata E.Pritz. ex Diels
  • Daphne genkwa Siebold & Zucc.
  • Daphne giraldii Nitsche
  • Daphne glomerata Lam.
  • Daphne gnidioides Jaub. & Spach
  • Daphne gnidium L.
  • Daphne gracilis E.Pritz.
  • Daphne grueningiana H.J.P.Winkl.
  • Daphne hekouensis H.W.Li & Y.M.Shui
  • Daphne holosericea (Diels) Hamaya
  • Daphne jarmilae Halda
  • Daphne jasminea Sm.
  • Daphne jezoensis Maxim.
  • Daphne kamtschatica Maxim.
  • Daphne kingdon-wardii Halda
  • Daphne kiusiana Miq.
  • Daphne koreana Nakai
  • Daphne kosaninii (Stoj.) Stoj.
  • Daphne laureola L.
  • Daphne limprichtii H.J.P.Winkl.
  • Daphne linoides (Hemsl.) Halda
  • Daphne longilobata (Lecomte) Turrill
  • Daphne ludlowii D.G.Long & Rae
  • Daphne luzonica C.B.Rob.
  • Daphne macrantha Ludlow
  • Daphne malyana Blecic
  • Daphne mauritanica Nieto Fel.
  • Daphne mezereum L.
  • Daphne miyabeana Makino
  • Daphne modesta Rehder
  • Daphne morrisonensis C.E.Chang
  • Daphne mucronata Royle
  • Daphne myrtilloides Nitsche
  • Daphne nana Tagawa
  • Daphne odora Thunb.
  • Daphne oleoides Schreb.
  • Daphne pachyphylla D.Fang
  • Daphne papyracea Wall. ex G. Don
  • Daphne penicillata Rehder
  • Daphne petraea Leyb.
  • Daphne pontica L.
  • Daphne pseudomezereum A.Gray
  • Daphne reginaldi-farreri Halda
  • Daphne rhynchocarpa C.Y.Chang
  • Daphne rodriguezii Texidor
  • Daphne rosmarinifolia Rehder
  • Daphne salicina H.Lév.
  • Daphne sericea Vahl
  • Daphne skipetarum Halda
  • Daphne sojakii Halda
  • Daphne sophia Kolenicz.
  • Daphne souliei (Lecomte) Aymonin
  • Daphne stapfii Bornm. & Keissl.
  • Daphne striata Tratt.
  • Daphne sureil W.W.Sm. & Cave
  • Daphne tangutica Maxim.
  • Daphne taurica Kotov
  • Daphne taylorii Halda
  • Daphne tenuiflora Bureau & Franch.
  • Daphne tripartita H.F.Zhou ex C.Y.Chang
  • Daphne velenovskyi Halda
  • Daphne wangeana (Hamaya) Halda
  • Daphne wolongensis C.D.Brickell & B.Mathew

Hybrids

Numerous natural and artificial hybrids are cultivated as ornamental plants. These include:

  • D. × burkwoodii[13] – D. cneorum × D. caucasica
  • D. × hendersonii Hodgkin ex C.D.Brickell – natural hybrid D. petraea × D. cneorum[3]
  • D. × napolitana Lodd. has gained the Royal Horticultural Society's Award of Garden Merit.[14] – origin not known[3]
  • D. × schlyteri – artificial hybrid D. cneorum × D. arbuscula[15]
  • D. × thauma Farrer – natural hybrid D. petraea × D. striata [3]

Distribution

Daphne is a Eurasian genus, being native to central and southern Europe and Asia,[5] from Britain[16] to Japan.[17] Some species are also found in north Africa. Two species, D. mezereum and D. laureola, have been introduced into North America.[5]

Uses

Two species, Daphne bholua and Daphne papyracea, both called lokta, are sustainably harvested in Nepal and Bhutan for paper production.[18]

Many species are cultivated as ornamental shrubs in gardens.[19] The smaller species are used as rock garden plants or, in the case of those more difficult to grow, as plants for the alpine house. It is recommended that they are grown in well drained but moisture-retentive soil, avoiding strongly acid conditions. Most species prefer a sunny position, although some are woodland plants (e.g. D. mezereum and D. pontica). Propagation is by seed, cuttings or layering.[3]

Toxicity

All parts of daphnes are toxic, the berries being particularly so. One active compound is daphnin, a glycoside, combining glucose with daphnetin. Some species have been shown to contain a further toxin, mezerein. Symptoms of ingestion include burning sensations and lesions of the mouth and upper digestive tract, gastroenteritis and diarrhoea, and in severe cases, damage to the kidneys (nephritis), irregular heart rhythm, and coma.[20][21]

  • Variation in flower and fruit colour
  • Daphne jezoensis
  • Daphne pseudomezereum
  • Daphne laureola
  • Daphne blagayana
  • Daphne glomerata
  • Daphne odora
  • Daphne petraea
  • Daphne mezereum – deciduous
  • Daphne giraldii – unripe fruits
  • Daphne gnidium – ripe fruits
  • Daphne jezoensis – ripe fruits

References
  1. "Plant Name Details for Daphne L.", The International Plant Names Index, retrieved 2017-11-23
  2. Sunset Western Garden Book, 1995, pp. 606–607
  3. Beckett, K., ed. (1993), Encyclopaedia of Alpines : Volume 1 (A–K), Pershore, UK: AGS Publications, ISBN 978-0-900048-61-6, pp. 371–376
  4. Wang, Yinzheng; Gilbert, Michael G.; Mathew, Brian F. & Brickell, Christopher (1994), "Daphne", in Wu, Zhengyi; Raven, Peter H. & Hong, Deyuan (eds.), Flora of China, Beijing; St. Louis: Science Press; Missouri Botanical Garden, retrieved 2012-01-31
  5. Nevling Jr., Lorin I. & Barringer, Kerry, "Daphne", in Flora of North America Editorial Committee (ed.), Flora of North America (online), eFloras.org, retrieved 2017-11-22
  6. Linnæus, Carl (1753), "Daphne", Species Plantarum (in Latin), 1, Stockholm, Sweden: Laurentius Salvius, p. 345, retrieved 2017-11-23
  7. "Thymelaea sanamunda", The Plant List, retrieved 2017-11-23
  8. Halda, Josef J. (1997), "Some nomenclatoric changes and new descriptions in the genus Daphne L." (PDF), Acta Musei Richnoviensis Sect. Nat., 4 (2): 67–70, archived from the original (PDF) on 2017-12-01, retrieved 2017-11-18
  9. Halda & Haldová (2001).
  10. "Search results for Daphne", The Plant List, retrieved 2017-11-19
  11. van der Bank, Michelle; Fay, Michael F. & Chase, Mark W. (2002), "Molecular Phylogenetics of Thymelaeaceae with particular reference to African and Australian genera", Taxon, 51 (2): 329–339, doi:10.2307/1554930, JSTOR 1554930
  12. Beaumont, Angela J.; Edwards, Trevor J.; Manning, John; Maurin, Olivier; Rautenbach, Marline; Motsi, Moleboheng C.; Fay, Michael F.; Chase, Mark W. & Van Der Bank, Michelle (2009), "Gnidia (Thymelaeaceae) is not monophyletic: taxonomic implications for Thymelaeoideae and a partial new generic taxonomy for Gnidia", Botanical Journal of the Linnean Society, 160 (4): 402–417, doi:10.1111/j.1095-8339.2009.00988.x
  13. RHS Plant Selector – Daphne × burkwoodii, retrieved 2013-06-14
  14. RHS Plant Selector - Daphne × napolitana, retrieved 2013-06-14
  15. Mail Order Daphne from Junker's Nursery (38a), Junker's Nursery, archived from the original on 2009-10-04, retrieved 2012-01-29
  16. Stace, Clive (2010), "Daphne", New Flora of the British Isles (3rd ed.), Cambridge, UK: Cambridge University Press, pp. 381–382, ISBN 978-0-521-70772-5
  17. Ohwi, Jisaburo (1965), Meyer, Frederick G. & Walker, Egbert H. (eds.), Flora of Japan (in English), Washington, D.C.: Smithsonian Institution, p. 644, ISBN 978-0-87474-708-9, retrieved 2017-11-21
  18. Lokta Daphne sp. (PDF), Asia Network for Sustainable Agriculture and Bioresources (ANSAB), archived from the original (PDF) on 2007-02-25, retrieved 2014-03-01
  19. Phillips, Roger & Rix, Martyn (1989), Shrubs, London: Pan Books, ISBN 978-0-330-30258-6, pp. 36–39
  20. Lewis, Robert A. (1998), "Daphne", Lewis' Dictionary of Toxicology, Boca Raton, etc.: Lewis Publishers, pp. 346–347, ISBN 978-1-56670-223-2, retrieved 2017-11-25
  21. Wink, M. (2009), "Mode of action and toxicology of plant toxins and poisonous plants", Mitteilungen aus dem Julius Kühn-Institut, 421: 93–112, retrieved 2017-11-25

Bibliography
  • Brickell, C.D. & Mathew, B. (1976), Daphne: The Genus in the Wild and in Cultivation, Woking: The Alpine Garden Society, OCLC 832501497
  • Halda, Josef J. & Haldová, Jarmila (2001), The Genus Daphne, Dobré: SEN, ISBN 978-80-86483-00-9
  • White, Robin (2006), Daphnes: A Practical Guide for Gardeners, Portland, UK: Timber Press, ISBN 978-0-88192-752-8
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