''Senecio inaequidens'', known as narrow-leaved ragwort and South African ragwort, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the daisy family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

Description

''Senecio inaequidens'' is a

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

chamaephyte A subshrub (Latin ''suffrutex'') or dwarf shrub is a short shrub, and is a woody plant. Prostrate shrub is a related term. "Subshrub" is often used interchangeably with "bush".Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Der ...

up to 1 m in height, often much ramified, with each stem ending in one or a few capitula yellow in colour, forming a loose floral display. A single plant produces 26 to 500 capitula each year, with approximately 90 florets, 74% of them developing a viable

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

. The leaves are linear, entire or almost so and without petioles. ''S. inaequidens'' exists as a

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

genotype and a

tetraploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

cytotype. Initially the diploid ''S. madagascarensis'' and ''S. harveianus'' were assumed to be different species; however molecular analysis showed that they only differ in cytotype.

Distribution

It is native to Southern Africa, including

Lesotho Lesotho ( ), officially the Kingdom of Lesotho, is a country landlocked country, landlocked as an Enclave and exclave, enclave in South Africa. It is situated in the Maloti Mountains and contains the Thabana Ntlenyana, highest mountains in Sou ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

Eswatini Eswatini ( ; ss, eSwatini ), officially the Kingdom of Eswatini and formerly named Swaziland ( ; officially renamed in 2018), is a landlocked country in Southern Africa. It is bordered by Mozambique to its northeast and South Africa to its no ...

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...

and

Botswana Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label=Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kalahar ...

Habitat

In its native habitat ''S. inaequidens'' occurs at elevations from sea level to 2,850 m in a wide range of naturally or anthropogenically disturbed habitats such as river banks, rocky slopes, heavily grazed or recently burned grasslands, and road verges. The tetraploid cytotype was only found in the uKhalhamba and Maloti mountain ranges, and this is the cytotype of ''S. inaequidens'' which was inadvertently exported to Europe. 20180726Senecio inaequidens2

Invasive spread

The plant is a widespread

neophyte A neophyte is a recent Initiation, initiate or Religious conversion, convert to a subject or belief. Neophyte may also refer to: Science * Neophyte (botany), a plant species recently introduced to an area As a proper noun Arts and entertainme ...

Europe 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 Continent#Subcontinents, subcontinent of Eurasia ...

and an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

in Central Europe. It was introduced through wool imports from Southern Africa. In Europe the ports of entry were Bremen, Calais, Mazamet, and Verviers. ''S. inaequidens'' commonly exists in ruderal habitats such as railroads, roads and motorways, vacant or disused land. Plants can be seen on disused land as

pioneer species Pioneer species are hardy species that are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by wildfire. Pioneer flora Some lichens grow on rocks without soil, so m ...

but so far often disappear in an

ecological succession Ecological succession is the process of change in the species structure of an ecological community over time. The time scale can be decades (for example, after a wildfire) or more or less. Bacteria allows for the cycling of nutrients such as ca ...

. In Central Europe where it first spread, the plant so far seems to use previously unused ecological niches. There does not seem a clear advantage over native vegetation, except in higher altitude. In the European Alps ecologists and farmers are worried that it has the advantage of invading grazing fields on the alm pastures. The furthest north it was found was

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

. ''S. inaequidens'' is also present in Korea and Taiwan. In South America and Australia the diploid variant '' S. madagascariensis'' is highly invasive.

Properties

''Senecio inaequidens'' contains

pyrrolizidine alkaloids Pyrrolizidine alkaloids (PAs), sometimes referred to as necine bases, are a group of naturally occurring alkaloids based on the structure of pyrrolizidine. Pyrrolizidine alkaloids are produced by plants as a defense mechanism against insect he ...

having hepatotoxic properties that are poisonous to mammals.

References

{{Taxonbar, from=Q939756 inaequidens Flora of South Africa Plants described in 1838 Taxa named by Augustin Pyramus de Candolle