Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

Home to the plants of the Sonoran, Chihuahuan and Mojave Deserts

Cirsium ochrocentrum, Yellowspine Thistle

Senecio flaccidus var. flaccidus, Threadleaf Ragwort

Senecio flaccidus var. flaccidus, Threadleaf Ragwort, Southwest Desert Flora Senecio flaccidus var. flaccidus, Threadleaf Ragwort, Southwest Desert Flora Senecio flaccidus var. flaccidus, Threadleaf Ragwort, Southwest Desert Flora   Senecio flaccidus var. flaccidus, Threadleaf Ragwort, Southwest Desert Flora

Scientific Name: Senecio flaccidus var. flaccidus
Common Name: Threadleaf Ragwort
Also Called: Treadleaf Groundsel, (Spanish: Hierba Ceniza)
Family: Asteraceae, Sunflower Family
Synonyms: (Senecio douglasii ssp. longilobus, Senecio douglasii var. jamesii, Senecio douglasii var. longilobus, Senecio filifolius, Senecio longilobus)
Status: Native
Duration: Perennial
Size: Up to 3 feet.
Growth Form: Forb/herb, subshrub; erect; woody near base; herbage usually tomentose with white hairs but with some glabrescent.
Leaves: Green; alternate; margins pinnatifid, linear to filiform segments, entire and revolute.
Flower Color: Yellow; showy, ray flowers usually 8 florets; slender yellow, disk flowers yellow or orange-yellow, numerous; clusters with few to many heads on branch tips; bracts or phyllaries subtending flower head campanulate, fruit is an achene.
Flowering Season: March to May or may flower year-round.
Elevation: 2,500 to 7,500 feet.
Habitat Preferences: Upper and lower desert, pinyon-juniper community, chaparral, mesas, slopes, dry washes, sandy or rocky soils and disturbed areas.
Recorded Range: In the central southern United States including; AZ, CO, KS, NM, OK, TX and UT. Also found in Baja California and northern Mexico.

U.S. Weed Information: No data available.
Invasive/Noxious Weed Information: No data available.
Wetland Indicator: No data available.
Threatened/Endangered Information: No data available.

Genus Information: 69 species in Senecio throughout all of North America. 13 species in Arizona. 3 varieties for Senecio flaccidus, 2 in Arizona:
Senecio flaccidus var. douglasii, Douglas' Ragwort,
Senecio flaccidus var. flaccidus, Threadleaf Ragwort (AZ) and
Senecio flaccidus var. monoensis, Smooth Threadleaf Ragwort (AZ).
Arizona varieties overlap.

Comments: Threadleaf Ragwort, variety "flaccidus"; is a common large subshrub similar in appearance to Smooth Threadleaf Ragwort, Senecio flaccidus var. monoensis, but may be differentiated in the field where varieties overlap by its silvery or canescent woolly appearance and comb-like pinnatifid leaves. Also see Lemmon's Ragwort, Senecio lemmonii.

The genus Senecio is known to contain alkaloids which may cause liver damage in livestock.

Date Profile Completed: 08/18/2012, rev 08/04/2014; Updated, 07/26/2015
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database - USGS, NRCS, ITIS, Standard Report Page, Date Generated: Sat Aug 18 2012 11:59:11 MDT
Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, as Senecio longilobus.
The Jepson Manual, for Senecio flaccidus: Citation: 08/04/2014
Theodore M. Barkley, FNA | Family List | FNA Vol. 20 | Asteraceae | Senecio, Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford. (accessed 08/18/2012, 08/04/2014)
SEINet for synonyms, scientific names and recorded geographic locations,