''Arfeuillea'' is a monotypic genus in the family

Sapindaceae The Sapindaceae are a family (biology), family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1,858 accepted species. Examples include Aesculus, horse chestnut, maples, ackee and lychee. The ...

with ''Arfeuillea arborescens'' as its only species. Commonly known as hop tree, this species is characterized by compound leaves arranged spirally around the branches, flowers with small white petals and larger red sepals, and dehiscent papery yellow fruits with two black seeds encased. It is native to

Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...

and

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

but is cultivated only and not found in the wild. The species serves as a

street tree Urban forestry is the care and management of single trees and tree populations in Urban area, urban settings for the purpose of improving the urban environment. Urban forestry involves both planning and management, including the programming of ...

across its native range and in

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

and

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

, and its antioxidant-rich leaves are included in many Thai herbal medicines.

Description

''Arfeuillea arborescens'' develops as a tree with a bushy, round

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...

. Its leaves are compound and include 3-4 pairs of entire (though sometimes serrate), elliptical leaflets, which are arranged spirally around the branches. The

flowers Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

are bisexual, have small white petals surrounded by larger red sepals, and are arranged in branched inflorescences. Fruits are simple, dehiscent, and golden yellow in color. They have three wings, are papery, and contain two large, ovular black seeds.

Distribution and habitat

''Arfeuillea aborescens'' is from southeast Asia, specifically

and

. However, wild specimens are rare. ''Arfeuillea aborescens'' is exclusively cultivated.

Taxonomy

There is only one species in this genus: ''Arfeuillea arborescens''. Once grouped in the ''

Koelreuteria ''Koelreuteria'' , also known as chinese lantern tree, is a genus of three species of flowering plants in the family Sapindaceae, native to southern and eastern Asia, as well as the island of Fiji. Many fossil species are also known, suggesting t ...

'' genus, a synonymous name for this species is ''Koelreuteria arborescens''. In calling it ''Arfeuillea arborescens'', Pierre, the botanist who first described the species, named it after his friend, ''Arfeuille''.

Evolution and phylogeny

''Arfeuillea arborescens'' is in the family

, the tribe Harpullieae, the subfamily

Dodonaeoideae Dodonaeoideae is a subfamily of flowering plants in the soapberry family, Sapindaceae. The subfamily includes 24 genera in two tribes, Dodonaeae and Doratoxyleae.Buerki S, Callmander MW, Acevedo-Rodriguez P, Lowry PP 2nd, Munzinger J, Bailey P, ...

, the group

Dodonaea ''Dodonaea'', commonly known as hop-bushes, is a genus of about 70 species of flowering plants in the soapberry family, Sapindaceae. The genus has a cosmopolitan distribution in tropical, subtropical and warm temperate regions of Africa, the Am ...

, and the monotypic genus ''Arfeuillea''. The subfamily Dodonaeoideae is characterized by its dehiscent fruits. ''Arfeuillea arborescens''’ closest relative is ''

Conchopetalum brachysepalum ''Conchopetalum'' is a genus of flowering plants belonging to the family Sapindaceae The Sapindaceae are a family (biology), family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1,858 acc ...

'', a member of Sapindaceae native to Madagascar.

Human uses

''Arfeuillea'' are cultivated only. They are mainly planted alongside streets in residential areas in Malaysia, Singapore, and Thailand, but they can also be used as a spice. Fresh leaves of ''Arfeuillea arborescens'' contain antioxidant properties, so they are included in many Thai medicinal herbs.

Hybrids

''Arfeuillea'' does not have any publicly documented hybrids outside of ''Arfeuillea arborescens''. Since it is cultivated, there is a possibility for man made hybrids to exist.

References

{{Taxonbar, from1=Q8203985, from2=Q15545936 Monotypic Sapindaceae genera Dodonaeoideae