*Senecio flaccidus var. monoensis, Smooth Threadleaf Ragwort
Common Name: Smooth Threadleaf Ragwort
Also Called: Green Groundsel, Mono Ragwort, Sand Wash Groundsel, Shrubby Butterweed
Family: Asteraceae, Sunflower Family
Synonyms: (Senecio filicifolius, Senecio lathyroides, Senecio longilobus, Senecio douglasii, Senecio douglasii var. monoensis, Senecio monoensis, Senecio pectinatus)
Size: Up to 3 feet.
Growth Form: Forb/herb, subshrub, glabrescent or glabrous, slender branches.
Leaves: Green; alternate, glabrous; slender; margins entire, revolute, pinnately divided into narrow thread-like (filiform) segments; leaves up to 4 inches resemble a hair comb.
Flower Color: Yellow; showy, ray flowers 8 to 13; slender yellow, disk flowers yellow or orange-yellow, numerous; clusters with few to many heads on branch tips; phyllaries subtending flower head campanulate; fruit an achene.
Flowering Season: March to May or year-round with sufficient rainfall; April to June and September to November in California.
Elevation: 1,000 to 6,000 feet; 2,000 to 6,500 feet in California.
Habitat Preferences: Upper and lower desert, pinyon-juniper community, chaparral; open areas, mesas, slopes, canyons, dry washes, sandy or rocky sites.
Recorded Range: Native to southwestern United States in (AZ, CA, NM, NV, TX, UT), also in Baja California and northern and central Mexico.
North America & US County Distribution Map for Senecio flaccidus var. monoensis.
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: In North America there are 70 species for Senecio. The Editors of Encyclopedia Britannica identify about 1,200 species distributed throughout the world.
In the Southwestern United States: Arizona has 13 species of genus, California has 25 species, Nevada has 15 species, New Mexico has 22 species, Texas has 9 species, Utah has 18 species. All data is approximate and subject to taxonomic changes.
Senecio flaccidus var. monoensis is 1 of 3 varieties found in the southwestern United States:
Senecio flaccidus var. douglasii, Douglas' Ragwort (CA, CO, KS),
Senecio flaccidus var. flaccidus, Threadleaf Ragwort (AZ, CO, NM, NV, OK, TX, UT) and
Senecio flaccidus var. monoensis, Smooth Threadleaf Ragwort (AZ, CA, NM, NV, TX, UT).
Arizona varieties overlap.
Comments: Smooth Threadleaf Ragwort, variety monoensis with its smooth, mostly glabrous features and comb-like pinnatifid leaves are key features that help to separate it from Threadleaf Ragwort, Senecio flaccidus var. flaccidus where varieties overlap. Senecio flaccidus var. monoensis intergrades with var. douglasii and with var. flaccidus in areas of range overlap.
The genus Senecio is known to contain alkaloids which may cause liver damage in livestock.