''Senecio flaccidus'', also known as threadleaf ragwort, is a member of the

daisy family Asteraceae () is a large family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the order Asterales. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger fam ...

. It is native from central to southwest North America, where it is common in gravelly and dry areas.

Description

Threadleaf ragwort is a fast-growing, short-lived (3 to 6 years) bushy

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

shrub growing to tall. It is covered by a white close wool. The stems are grooved and the branches are thin,

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

above and woody near the base. The

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, ...

are long. They are alternate and deeply

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

, divided into five to nine narrow lobes. These are gray-green above and

tomentose Trichomes (; ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant ...

. From April to September appear showy yellow flowering heads, across. They have eight to thirteen sterile ray flowers, and purplish brown disk florets that produce the seeds. ;Seeds:

Dicotyledon The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, ...

fruits; each a -long

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...

that is ribbed and hoary, covered with short white hairs.

Taxonomy and names

The species was formerly recorded as ''Senecio douglasii'' (in honor of the botanist David Douglas). The name threadleaf ragwort stems from the appearance of the leaves. Other common names include: threadleaf groundsel, bush senecio, creek senecio, shrubby butterweed, comb butterweed, smooth threadleaf ragwort, Mono ragwort, Douglas ragwort, Douglas groundsel, sand wash groundsel, felty groundsel, old man, yerba cana, squawweed, and cenicillo.

Subspecies

*''Senecio flaccidus'' Less. var. ''flaccidus'' *''Senecio douglasii'' DC. var. ''longilobus'' (Benth.) L.D. Benson *''Senecio douglasii'' DC. var. ''jamesii'' (Torr. & A. Gray) Ediger ex Correll & M.C. Johnst. *''Senecio douglasii'' DC. ssp. ''longilobus'' (Benth.) W.A. Weber *''Senecio flaccidus'' Less. var. ''monoensis'' (Greene) B. L. Turner & T. M. Barkley *''Senecio flaccidus'' Less. var. ''douglasii'' (DC.) B. L. Turner & T. M. Barkley *''Senecio flaccidus'' var. ''flaccidus''

Distribution and habitat

''S. flaccidus'' can be found from the central to the southwestern United States, overlapping with the

Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...

region. It is native between

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

and

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

, south to

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

, and much of northern and central Mexico. Like other members of its genus, it prefers disturbed habitats, especially overgrazed rangelands, dried-up streambeds and desert grasslands. It can be found at altitudes between . It is common in gravelly washes, dry creek beds, along roads and trails, and mostly away from the coast. Native :America ::North-Central U.S.:

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

::Northwestern:

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

::South-Central:

::Southwestern:

, ::Northern Mexico: Chihuahua,

Coahuila Coahuila, formally Coahuila de Zaragoza, officially the Free and Sovereign State of Coahuila de Zaragoza, is one of the 31 states of Mexico. The largest city and State Capital is the city of Saltillo; the second largest is Torreón and the thi ...

Durango Durango, officially the Free and Sovereign State of Durango, is one of the 31 states which make up the Political divisions of Mexico, 32 Federal Entities of Mexico, situated in the northwest portion of the country. With a population of 1,832,650 ...

San Luis Potosí San Luis Potosí, officially the Free and Sovereign State of San Luis Potosí, is one of the 32 states which compose the Federal Entities of Mexico. It is divided in 59 municipalities and is named after its capital city, San Luis Potosí. It ...

Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...

Zacatecas Zacatecas, officially the Free and Sovereign State of Zacatecas, is one of the Political divisions of Mexico, 31 states of Mexico. It is divided into Municipalities of Zacatecas, 58 municipalities and its capital city is Zacatecas City, Zacatec ...

::Central Mexico:

Aguascalientes Aguascalientes, officially the Free and Sovereign State of Aguascalientes, is one of the 32 states which comprise the Political divisions of Mexico, Federal Entities of Mexico. At 22°N and with an average altitude of above sea level it is pre ...

Guanajuato Guanajuato, officially the Free and Sovereign State of Guanajuato, is one of the 32 states that make up the Political divisions of Mexico, Federal Entities of Mexico. It is divided into Municipalities of Guanajuato, 46 municipalities and its cap ...

Hidalgo Hidalgo may refer to: People * Hidalgo (nobility), members of the Spanish nobility * Hidalgo (surname) Places Mexico :''Most, if not all, named for Miguel Hidalgo y Costilla (1753–1811)'' * Hidalgo (state), in central Mexico * Hidalgo, Coah ...

Jalisco Jalisco, officially the Free and Sovereign State of Jalisco, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entities of Mexico. It is located in western Mexico and is bordered by s ...

(n.e.),

Veracruz Veracruz, formally Veracruz de Ignacio de la Llave, officially the Free and Sovereign State of Veracruz de Ignacio de la Llave, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entit ...

Current :America ::North-Central: Kansas, Oklahoma,

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

::Northwestern: Colorado ::South-Central: New Mexico, Texas ::Southwestern: Arizona,

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

, Utah ::Northern Mexico: Chihuahua, Coahuila, Durango, San Luis Potosí, Sonora, Zacatecas,

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

::Central Mexico: Aguascalientes, Baja Norte, Guanajuato, Hidalgo, Jalisco (n.e.), Veracruz

Ecology

Colonizing disturbed areas including over-grazed lands, ''S. flaccidus'' helps to achieve a quick

groundcover Groundcover or ground cover is any plant that grows low over an area of ground, which protects the topsoil from erosion and drought. In a terrestrial ecosystem, the ground cover forms the layer of vegetation below the shrub layer known as the ...

and helps to stabilize the soil for longer-lived perennials.

Toxicity

The species is poor forage for cattle and horses due to the

alkaloids Alkaloids are a broad class of naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large variety of organisms i ...

contained in the plant; these cause liver disease when consumed in large quantities. Also known as ''Senecio longilobus'', one of the alkaloids found in this species is longilobine, as well as senecionine, seneciphylline, florosenine, otonecine-based florosenine, and retrorsine.

References

External links

* * * {{Taxonbar, from=Q3025700 flaccidus Flora of Central Mexico Flora of Northeastern Mexico Flora of Northwestern Mexico Flora of New Mexico Flora of Texas Flora of the United States Flora of Northern America