The genus Helwingia consists of or rarely small trees native to eastern Asia, the Himalayas, and northern Indochina. It is the only genus in the family Helwingiaceae.[ Kew World Checklist of Selected Plant Families][ Flora of China Vol. 14 Page 227 青荚叶属 qing jia ye shu Helwingia Willdenow, Sp. Pl. 4: 634, 716. 1806, nom. cons., not Helvingia Adanson (1763). ]
Description
The plants have alternate, evergreen or deciduous
leaf and small
that are epiphyllous (growing from the leaf surface). During development, the flowers appear separate from the leaves,, eventually fusing with the leaf midrib.
Flowers are small and yellow-green or purple, followed by red or black berries. Plants are
Dioecy.
Epiphyllous inflorescences
This trait is rather unusual among plants. This atypical floral position upon a leaf is believed to be an adaption to insect pollination. Pollinators which are too large to be supported by the floral pedicels, land on the leaf surface and can pollinate the flowers, which would not be able to support the pollinators on their own.
Taxonomy
The APG II classification (2003) places them in the order
Aquifoliales, along with the
Holly and
Phyllonomaceae, which also has epiphyllous flowers.
The family Helwingiaceae does not exist in the
Cronquist system, which places this genus in the Cornaceae (dogwood family). Helwingia has also previously been placed in the Araliaceae (ginseng family).
The family is named for botanist Georg Andreas Helwing.
Species
Species adapted from the World Checklist of Selected Plant Families:
[
]
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Helwingia chinensis Batalin - Thailand, Myanmar, China: Gansu, Guizhou, Hubei, Hunan, Shaanxi, Sichuan, Tibet, Yunnan
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Helwingia himalaica Hook.f. & Thomson ex C.B.Clarke - Thailand, Myanmar, Bhutan, Nepal, India: Assam, Sikkim, China: Tibet, Chongqing, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Sichuan, Yunnan
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Helwingia japonica (Thunb.) F.Dietr. - Japan (incl. Ryukyu Islands), Korea, Taiwan, Myanmar, Bhutan, Vietnam, India: Assam, Sikkim, China: Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Shanxi, Sichuan, Yunnan, Zhejiang
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Helwingia omeiensis (W.P.Fang) H.Hara & S.Kuros. - China: Gansu, Guangxi, Guizhou, Hubei, Hunan, Shaanxi, Sichuan, Yunnan
External links
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Aquifoliales - Angiosperm Phylogeny Website, consulted 2007-01-26.
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Helwingiaceae , Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 29 July 2006.
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Helwingiaceae from NCBI-Taxonomy
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Helwingiaceae, USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN Online Database). National Germplasm Resources Laboratory, Beltsville, Maryland. Consulted 2007-01-26.
