Calycanthus, called sweetshrub,[2] is a genus of flowering plants in the family Calycanthaceae. The genus includes two to four species depending on taxonomic interpretation; three are accepted by most 21st century sources.
Description
Calycanthus plants are deciduousshrubs, growing to 4 m (13 ft) tall. The leaves are opposite and undivided. The plants are aromatic.[3][4][5][6] The flowers are typical of the family Calycanthaceae in lacking distinct sepals and petals, but instead having spirals of tepals.[7] Flowers are produced from spring onwards, until October in the case of C. occidentalis.[8] The flowers of the two North American species are scented, 4–7 cm (1.6–2.8 in) across, with numerous dark red to burgundy to purplish brown tepals. C. chinensis has broader tepals, the outer ones white flushed with pink, the inner ones mostly yellow with purple marks at the base.[5] The fruit is an elliptical dry capsule, containing numerous seeds.[9]
C. floridus and C. occidentalis are pollinated by beetles. Their flowers produce small protein-rich growths that feed beetle pollinators.[10]C. occidentalis has been shown to produce chemicals that mimic fermenting fruits that attract beetles in the families Nitidulidae and Staphylinidae.[11]
Taxonomy
The genus Calycanthus was created by Carl Linnaeus in 1759,[12] with the sole species Calycanthus floridus.[13] In 1762, he added Calycanthus praecox, now treated as Chimonanthus praecox.[14]
Phylogeny and evolution
A 2006 molecular phylogenetic study of the family Calycanthaceae found that the three widely recognized species of Calycanthus formed a monophyletic group. Relationships among the three species differed depending on whether chloroplast or nuclear data was used. A cladogram obtained by combining the two is shown below.[10]
The family Calycanthaceae may have had a Gondwanan origin. The sole Australian representative, Idiospermum australiense, would then represent an ancient relic, probably having diverged in the Cretaceous. There are no extant South American members of the family, although fossils are known. Calycanthus may have migrated into North America from eastern Asia, or may have originated in South America, moved northwards and then spread to eastern Asia.[10]
Calycanthus brockianus Ferry & Ferry f.—north central Georgia; has greenish rather than brownish red flowers, and may only be a triploid color variant of C. floridus.[5]
Calycanthus chinensis (W.C.Cheng & S.Y.Chang) W.C.Cheng & S.Y.Chang ex P.T.Li (syn. Sinocalycanthus sinensis)—Chinese sweetshrub, Chinese wax shrub, native to eastern China, with white flowers[15]
C. chinensis has a confused taxonomic history. It was first described in 1963 as Calycanthus chinensis by W.C. Cheng and S.Y. Chang, but invalidly because two different collections were both given as holotypes. The authors then described it validly in 1964 in their new genus Sinocalycanthus. In 1979, P.T. Li rejected the genus Sinocalycanthus, and validated the original name Calycanthus chinensis.[5]
C. chinensis–Chinese sweetshrub
C. floridus—eastern sweetshrub
C. occidentalis—western sweetshrub
Cultivation
The earliest illustration of Calycanthus floridus, from a work published from 1731 onwards
Calycanthus floridus is planted in gardens, as a specimen shrub, or for hedges.[22][23] The English naturalist Mark Catesby drew it as the support for the bird he called "Garrulus Carolinensis The Chatterer" (now Bombycilla cedrorum) in a work published from 1731 onwards. He described the shrub as growing in "remote and hilly parts" and having bark "as odoriferous as cinnamon".[24] The colonial planters of the Carolinas transplanted it into their gardens, and the botanist Peter Collinson described it to Linnaeus and imported it into England from Charleston in the Province of South Carolina around 1756.[25][page needed]
Calycanthus chinensis was introduced into cultivation in both the United States and the United Kingdom from the Shanghai Botanical Garden in the 1980s.[7][5] It has since been used extensively in the breeding of cultivars.[7]
Hybridization
Several hybrids and hybrid cultivars have been produced, with the intention of combining the larger flower size of C. chinensis with the colour and scent of the two North American species, as well as their greater hardiness. The hybrid between C. chinensis and C. floridus has been named C. × raulstonii. It combines the larger flowers of C. chinesis with the flower color of C. floridus. The original cross has been given the cultivar name 'Hartlage Wine' after the student, Richard Hartlage, who made the first crosses. Further crosses have been made. 'Venus' involves C. occidentalis as well.[5][7]
'Aphrodite' (C. chinensis × C. occidentalis) – US; large reddish-purple flowers with yellow marks on the inner tepals, borne on relatively long stalks; long flowering season
'Hartlage Wine' (C. × raulstonii) – US, 1991; resembles C. chinensis in leaf and flower size, with the flower colour of C. floridus; may reach 2 m (7 ft) in height; given the Royal Horticultural Society's Award of Garden Merit[28]
'Hongyun' (C. × raulstonii) – China, 2001; large flowers of C. chinensis with the red colour of C. floridus
'Solar Flare' (C. × raulstonii) – US, 2003–2006; similar to 'Hartlage Wine' but with larger and thicker leaves and smaller flowers; appears to be hardier to frost than 'Hartlage Wine'
'Venus' (C. × raulstonii × [C. chinensis × C. occidentalis]) – large white flowers, marked with yellow and purple at the centre; strongly fragrant
Calycanthus oil, distilled from the flowers, is an essential oil used in some quality perfumes.[31]
References
^ abc"Calycanthus L."Plants of the World Online. Board of Trustees of the Royal Botanic Gardens, Kew. Retrieved 9 February 2021.
^Johnson, George P. "Calycanthus". In Flora of North America Editorial Committee (ed.). Flora of North America (online). eFloras.org. Retrieved 9 February 2021.
^Johnson, George P. "Calycanthus floridus". In Flora of North America Editorial Committee (ed.). Flora of North America (online). eFloras.org. Retrieved 9 February 2021.
^Johnson, George P. "Calycanthus occidentalis". In Flora of North America Editorial Committee (ed.). Flora of North America (online). eFloras.org. Retrieved 9 February 2021.
^Li, Bingtao & Bartholomew, Bruce. "Calycanthus". In Wu, Zhengyi; Raven, Peter H. & Hong, Deyuan (eds.). Flora of China (online). eFloras.org. Retrieved 9 February 2021.
^ abcdeHsu, Eric (March 2018). "An overview of Calycanthus". The Plantsman. New Series. 17 (1): 32–39.
^Catesby, Mark (1731–1747). "Garrulus Carolinensis". The Natural History of Carolina, Florida and the Bahama Islands. Vol. I (1st ed.). London: self-published. p. 46. Archived from the original on 24 October 2019. Retrieved 10 February 2021. (The plant is given Linnaeus's name Calycanthus floridus in the table of contents of the 3rd edition.)
^Coats, A. (1992) [first published 1964]. Garden Shrubs and their Histories. New York: Simon and Schuster. ISBN978-0-671-74733-6.
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