Senecio flaccidus

Senecio flaccidus, formerly recorded as Senecio douglasii (in honor of the botanist David Douglas), member of the daisy family and genus Senecio also known as threadleaf ragwort (and 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 or cenicillo), is a native of the southwestern Great Plains of North America.

Description
Threadleaf ragwort is a fast-growing, short-lived (3 to 6 years) bushy perennial shrub growing to 4 ft; common in gravelly washes, dry creek beds, along roads and trails and mostly away from the coast.


 * Leaves and Stems: Branched and bushy, Senecio flaccidus gets its common name from its white, threadlike, bent and matted, tomentose leaves; alternate and deeply pinnate, divided into five to nine narrow linear segments, glabrous, having no hairs or projections, gray-green above, 1 to 4 in long. The principal leaves often have auxiliary clusters of smaller leaves. The stems are grooved and the branches are thin, herbaceous above and woody near the base.


 * Flowers: Showy flowering heads of yellow ray flowers, 3 – across; eight to thirteen sterile rays, purplish brown disk florets that produce the seeds.


 * Seeds: Dicotyledon fruits; each a 1/8 in long achene ribbed and hoary, covered with short white hairs.

Toxicity
Colonizing disturbed areas including over-grazed lands, Senecio flaccidus helps to achieve a quick ground cover and helps to stabilize the soil for longer-lived perennials but in this situation makes poor foraging for cattle and horses due to the alkaloids contained in the plant which 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.

Distribution
Like many Senecio Senecio flaccidus likes disturbed habitats, this one preferring overgrazed rangelands, dried up stream beds and desert grasslands; at altitudes above 1800 ft and below 6500 ft.

Native
 * America
 * North-Central: Kansas, Oklahoma
 * Northwestern: Colorado
 * South-Central: New Mexico, Texas
 * Southwestern: Arizona, Utah
 * Northern Mexico: Chihuahua, Coahuila, Durango, San Luis Potosí, Sonora, Zacatecas
 * Central Mexico: Aguascalientes, Guanajuato, Hidalgo, Jalisco (n.e.), Veracruz

Current
 * America
 * North-Central: Kansas, Oklahoma, Wyoming
 * Northwestern: Colorado
 * South-Central: New Mexico, Texas
 * Southwestern: Arizona, California, Nevada, Utah
 * Northern Mexico: Chihuahua, Coahuila, Durango, San Luis Potosí, Sonora, Zacatecas, Baja California
 * Central Mexico: Aguascalientes, Baja Norte, Guanajuato, Hidalgo, Jalisco (n.e.), Veracruz

Subspecies which are synonyms

 * 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