Helwingia
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The
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
''Helwingia'' consists of
shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...
s or rarely small trees native to eastern
Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
, the
Himalayas The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of h ...
, and northern
Indochina Mainland Southeast Asia (historically known as Indochina and the Indochinese Peninsula) is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to th ...
. It is the only genus in the
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Helwingiaceae.Kew World Checklist of Selected Plant Families
/ref>


Description

The plants have alternate, evergreen or deciduous
leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...
and small
inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
s 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
dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...
.


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 The Aquifoliales are an order of flowering plants, including the Aquifoliaceae (holly) family, and also the Helwingiaceae (2-5 species of temperate Asian shrubs) and the Phyllonomaceae (4 species of Central American trees and shrubs). In 2001, ...
, along with the hollies and Phyllonomaceae, which also has epiphyllous flowers. The family Helwingiaceae does not exist in the Cronquist classification (1981), which places this genus in the
Cornaceae The Cornaceae are a cosmopolitan family of flowering plants in the order Cornales. The family contains approximately 85 species in two genera, '' Alangium'' and '' Cornus''. They are mostly trees and shrubs, which may be deciduous or evergreen, ...
(dogwood family). ''Helwingia'' has also previously been placed in the
Araliaceae The Araliaceae are a family of flowering plants composed of about 43 genera and around 1500 species consisting of primarily woody plants and some herbaceous plants commonly called the ginseng family. The morphology of Araliaceae varies widely ...
(ginseng family). The family is named for botanist Georg Andreas Helwing.


Species

Species adapted from the
World Checklist of Selected Plant Families The World Checklist of Selected Plant Families (usually abbreviated to WCSP) was an "international collaborative programme that provides the latest peer reviewed and published opinions on the accepted scientific names and synonyms of selected p ...
: # '' Helwingia chinensis'' Batalin - Thailand, Myanmar, China: Gansu, Guizhou, Hubei, Hunan, Shaanxi, Sichuan, Tibet, Yunnan # '' 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 # '' 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 # ''
Helwingia omeiensis The genus (biology), genus ''Helwingia'' consists of shrubs or rarely small trees native to eastern Asia, the Himalayas, and northern Indochina. It is the only genus in the family (biology), family Helwingiaceae. Description The plants have alte ...
'' (W.P.Fang) H.Hara & S.Kuros. - China: Gansu, Guangxi, Guizhou, Hubei, Hunan, Shaanxi, Sichuan, Yunnan


References


External links


Aquifoliales - Angiosperm Phylogeny Website
consulted 2007-01-26.

, Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 29 July 2006. ** Also se


Helwingiaceae
from ''NCBI-Taxonomy''
Helwingiaceae
USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN Online Database). National Germplasm Resources Laboratory, Beltsville, Maryland. Consulted 2007-01-26. {{Taxonbar, from1=Q132079, from2=Q11862231 Aquifoliales Asterid genera Dioecious plants