''Phellodendron'', or cork-tree, is a genus of

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, a ...

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...

trees in the family Rutaceae, native to east and northeast

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

. It has leathery, pinnate leaves and yellow, clumped

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

s. The name refers to the thick and corky

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, ...

of some (but not all) species in the genus.

Fossil record

''Phellodendron'' seeds are known from the Early

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...

of eastern North America, from the Mid

to the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

and from the Pliocene of

and Japan. One

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

seed of ''Phellodendron'' has been extracted from bore hole samples of the Middle Miocene fresh water deposits in Nowy Sacz Basin, West Carpathians,

Poland Poland, officially the Republic of Poland, , is a country in Central Europe. Poland is divided into Voivodeships of Poland, sixteen voivodeships and is the fifth most populous member state of the European Union (EU), with over 38 mill ...

. Several ''Phellodendron'' macrofossils have been recovered from the late

Zanclean The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma (million years ago) and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, and ...

stage of

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pocapaglia,

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

Cultivation and uses

As an

ornamental plant Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that ...

, ''Phellodendron'' is a tree for all seasons. In spring it has yellow flowers, in summer it provides foliage and shade, in fall the leaves turn bright yellow, and the textured bark and winding branches add interest in the winter. The female bears black

drupe In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part ( exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kerne ...

s that attract

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s and other wildlife through the late fall and winter. The cork-tree is resistant to drought and

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

s, and it can thrive in a variety of

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

s. It is hardy to zone 4 and it is easy to maintain, sometimes to the point of being

invasive Invasive may refer to: *Invasive (medical) procedure *Invasive species *Invasive observation, especially in reference to surveillance *Invasively progressive spread of disease from one organ in the body to another, especially in reference to cancer ...

. One drawback is that the drupes fall and scatter, which may be undesirable on a formal

lawn A lawn is an area of soil-covered land planted with grasses and other durable plants such as clover which are maintained at a short height with a lawnmower (or sometimes grazing animals) and used for aesthetic and recreational purposes. ...

. The bark in some species is thick, resembling that of the

cork oak ''Quercus suber'', commonly called the cork oak, is a medium-sized, evergreen oak tree in the section ''Quercus'' sect. ''Cerris''. It is the primary source of cork for wine bottle stoppers and other uses, such as cork flooring and as the co ...

, but is not thick enough for commercial cork production. It has been used to produce a yellow dye. One species, '' Phellodendron amurense'' (Chinese: 黄柏; pinyin: huáng bǎi; or 黄檗; pinyin: huáng bò; Russian: Бархат амурский "Barkhat Amurskiy", also бархатное дерево, пробковое дерево), is one of the 50 fundamental herbs used in

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medicine, alternative medical practice drawn from traditional medicine in China. It has been described as "fraught with pseudoscience", with the majority of its treatments having no logica ...

. Recently, ''Phellodendron'' has also attracted scientific attention because of the phytochemicals it produces: * Berberine has antibacterial and anti-fungal properties * Jatrorrhizine may be anti-mutagenic * Phellodendrine has promise as an immune suppressant * Palmatine may be a vasodilator The phytochemical descriptions are included for informational purposes only and not for treatment purposes. The research at this stage is very preliminary. Traditionally, the

is the principal part of the plant used medicinally, although oil from the fruit is also used. The species grows in Northern China, and in the

Khabarovsk Khabarovsk ( rus, Хабaровск, a=Хабаровск.ogg, r=Habárovsk, p=xɐˈbarəfsk) is the largest city and the administrative centre of Khabarovsk Krai, Russia,Law #109 located from the China–Russia border, at the confluence of th ...

and Primorskiy regions of

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eigh ...

. Already identified as a significant forest invader in the mid-Atlantic region, ''Phellodendron amurense'' is an emerging species of concern in New England, and is identified as invasive or having invasive tendencies by state and private conservation authorities. Because the fruit is plentiful and high in sugars, Amur cork-tree attracts birds and mammals which help disperse its seeds. Because of its phytochemical profile and because the seedlings grow thickly, ''Phellodendron'' can out-compete other species. By suppressing reproduction of native hardwoods, Amur cork-tree can come to dominate native forests under favorable conditions. As a relatively new species of concern, its invasion biology and response to control are not well understood.

References

{{Taxonbar, from=Q1539986 Zanthoxyloideae Zanthoxyloideae genera Flora of Northeast Asia Trees of China Medicinal plants Dioecious plants