Rhamnus cathartica
Encyclopedia
Rhamnus cathartica is a species in the family Rhamnaceae
, native to Europe
, northwest Africa
, and western Asia
, from the central British Isles
south to Morocco
, and east to Kyrgyzstan
. It was introduced to North America as an ornamental shrub in the early 19th century or perhaps before.
shrub
or small tree growing up to 10 m tall, with grey-brown bark and spiny branches. The leaves
are elliptic to oval, 2.5–9 cm long and 1.2–3.5 cm broad; they are green, turning yellow in autumn, and are arranged somewhat variably in opposite to subopposite pairs or alternately. The flower
s are yellowish-green, with four petals; they are dioecious
and insect pollinated. The fruit
is a globose black drupe
6–10 mm diameter containing two to four seed
s; it is mildly poison
ous for people, but readily eaten by bird
s, which disperse the seeds in their droppings.
whose shade prevents the establishment of native trees or shrubs. It has become the target of efforts to eradicate it from home sites, parks and woodland areas. It is difficult to control because it sprouts vigorously and repeatedly from the root collar following cutting, girdling, or burning, though it can be controlled by applying concentrated herbicide to the cut stem.
The species was originally named by Linnaeus as Rhamnus catharticus, but this spelling was corrected to cathartica as the genus name Rhamnus is of feminine gender.
The wood is hard and dense, but little-used.
It is a food plant of the Brimstone butterfly. The sulphur-yellow males are indicative of the plant's presence.
This species is the alternate host for the important rust disease of cerals caused by Puccinia coronata
. R. cathartica is also the primary overwintering host in North America for an important agricultural pest of soybean
s, the soybean aphid
.
and sometimes invasive in parts of North America
. R. cathartica has a competitive advantage compared to native trees and shrubs in North America because it leafs out before native species. Soil in woodlands dominated by R. cathartica was higher in nitrogen
, pH
, and water content that soil in woodlands relatively free of R. cathartica, probably because R. cathartica has high levels of nitrogen
in its leaves and these leaves rapidly decompose.
R. cathartica is also associated with invasive European earthworms (Lumbricus
sp.) in the northern Midwest. Removing R. cathartica led to a decrease of invasive earthworm biomass of around 50%.
Rhamnaceae
Rhamnaceae, the Buckthorn family, is a large family of flowering plants, mostly trees, shrubs and some vines.The family contains 50-60 genera and approximately 870-900 species. The Rhamnaceae have a worldwide distribution, but are more common in the subtropical and tropical regions...
, native to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, northwest Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, and western Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, from the central British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
south to Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
, and east to Kyrgyzstan
Kyrgyzstan
Kyrgyzstan , officially the Kyrgyz Republic is one of the world's six independent Turkic states . Located in Central Asia, landlocked and mountainous, Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east...
. It was introduced to North America as an ornamental shrub in the early 19th century or perhaps before.
Description
Rhamnus cathartica is a deciduousDeciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
or small tree growing up to 10 m tall, with grey-brown bark and spiny branches. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are elliptic to oval, 2.5–9 cm long and 1.2–3.5 cm broad; they are green, turning yellow in autumn, and are arranged somewhat variably in opposite to subopposite pairs or alternately. The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are yellowish-green, with four petals; they are dioecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
and insect pollinated. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a globose black drupe
Drupe
In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...
6–10 mm diameter containing two to four seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s; it is mildly poison
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
ous for people, but readily eaten by bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, which disperse the seeds in their droppings.
Cultivation
The Common Buckthorn, Rhamnus cathartica, is shade-tolerant, moderately fast-growing and short-lived. This species is a tough, durable tree which adapts to urban or suburban environments, and virtually any area it is dispersed in. It is widely regarded as a major invasive speciesInvasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
whose shade prevents the establishment of native trees or shrubs. It has become the target of efforts to eradicate it from home sites, parks and woodland areas. It is difficult to control because it sprouts vigorously and repeatedly from the root collar following cutting, girdling, or burning, though it can be controlled by applying concentrated herbicide to the cut stem.
The species was originally named by Linnaeus as Rhamnus catharticus, but this spelling was corrected to cathartica as the genus name Rhamnus is of feminine gender.
Cultivation and uses
The bark and fruit were used as a purgative in the past, though their potentially dangerous violent action and side effects means they are now rarely used.The wood is hard and dense, but little-used.
It is a food plant of the Brimstone butterfly. The sulphur-yellow males are indicative of the plant's presence.
This species is the alternate host for the important rust disease of cerals caused by Puccinia coronata
Puccinia coronata
Puccinia coronata is a plant pathogen and causal agent of oat crown rust and barley crown rust. The pathogen occurs worldwide infecting both wild and cultivated oats. It is a relatively new disease of barley in North America. It was first found in 1992 in a barley breeding nursery near Clay...
. R. cathartica is also the primary overwintering host in North America for an important agricultural pest of soybean
Soybean
The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean which has numerous uses...
s, the soybean aphid
Soybean aphid
The soybean aphid is an insect pest of soybean that is exotic to North America. The soybean aphid is native to Asia. It has been described as a common pest of soybeans in China and as an occasional pest of soybeans in Indonesia, Japan, Korea, Malaysia, the Philippines, and Thailand...
.
Invasive species - North America
The species is naturalisedNaturalisation (biology)
In biology, naturalisation is any process by which a non-native organism spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised....
and sometimes invasive in parts of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. R. cathartica has a competitive advantage compared to native trees and shrubs in North America because it leafs out before native species. Soil in woodlands dominated by R. cathartica was higher in nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
, and water content that soil in woodlands relatively free of R. cathartica, probably because R. cathartica has high levels of nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
in its leaves and these leaves rapidly decompose.
R. cathartica is also associated with invasive European earthworms (Lumbricus
Lumbricus
Lumbricus contains some of the most commonly seen earthworms in Europe. The genus has nearly 700 valid species.Characteristics of some commonly encountered species are:...
sp.) in the northern Midwest. Removing R. cathartica led to a decrease of invasive earthworm biomass of around 50%.
External links
- Biological and Control Information from the Invading Species Awareness Program Invading Species.com
- Information and Resources on Common Buckthorn in Ontario Most Unwanted - Common Buckthorn