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. monoensis, Smooth Threadleaf Ragwort

Smooth Threadleaf Ragwort has showy bright yellow flowers that bloom from March through May or later with sufficient monsoon rainfall. Senecio flaccidus var. monoensis Smooth Threadleaf Ragwort is of the genus Senecio which as a group have similar technical characteristics found in the phyllaries surrounding the “flower” head. One characteristic is the black or dark spots on the pointed tips of the phyllaries. Senecio flaccidus var. monoensis Smooth Threadleaf Ragwort is similar to Threadleaf Ragwort, Senecio flaccidus var. flaccidus but its stems are smoother, lacking surface hairs which are often found on the latter. Note the smooth or naked stems in the photo. Senecio flaccidus var. monoensis Smooth Threadleaf Ragwort is a native perennial found in the southwest United States in the upper and lower deserts in open areas, mesas, slopes, canyons, dry washes and sandy or rocky sites. Senecio flaccidus var. monoensis

Scientific Name: Senecio flaccidus var. monoensis
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)

Status: Native

Duration: Perennial

Size: Up to 3 feet (91 cm) or more.

Growth Form: Forb/herb, subshrub, glabrescent or glabrous, slender branches.

Leaves: Green; leaves arranged alternately on stems and branches; leaves slender and without hairs (glabrous); margins entire, revolute, pinnately divided into narrow comb-like (filiform) segments; up to 4 inches (10 cm).

Flower Color: Yellow; large , 3 to 4 inches (8-10 cm) and showy; flower heads on tips of branches, 1 or many heads in clusters; flower heads with both ray and disk florets; bracts subtending heads campanulate; fruit an cypsela.

Flowering Season: March, April to October, November

Elevation: 1,000 to 6,000 feet (305-1,829 m); 2,000 to 6,500 feet (610-1,981 m) 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: Smooth Threadleaf Ragword is found mostly in the southwestern United States in AZ, CA, NM, NV, TX, UT. This variety is also Native to Baja California and northern Mexico.

North America & US County Distribution Map for Senecio flaccidus var. monoensis.

North America species range map for Smooth Threadleaf Ragwort, Senecio flaccidus var. monoensis:

North America species range map for Smooth Threadleaf Ragwort, Senecio flaccidus var. monoensis: Click image for full size map.
Click image for full size map

U.S. Weed Information: Unknown
Invasive/Noxious Weed Information: Unknown
Wetland Indicator: Unknown
Threatened/Endangered Information: Unknown

Genus Information: In North America there are 71 species for Senecio. Worldwide, The Plant List includes 1,587 accepted species names and a further 871 scientific names of infraspecific rank for Senecio.

The genus Senecio was published in 1753 by Carl Linnaeus, (1707-1778).

In the Southwestern United States: Arizona has 13 species of Senecio, California has 25 species, Nevada has 15 species, New Mexico has 22 species, Texas has 9 species, Utah has 18 species. Data approximate and subject to revision.

There are 3 varieties in Senecio flaccidus;
Senecio flaccidus var. douglasii, Douglas' Ragwort (CA, CO, KS);
Senecio flaccidus var. flaccidus, Threadleaf Ragwort (AZ, CO, NM, NV, OK, TX, UT);
Senecio flaccidus var. monoensis, Smooth Threadleaf Ragwort (AZ, CA, NM, NV, TX, UT).

Comments: The flowers of Threadleaf Groundsel (Senecio flaccidus) and it's sub-species are too similar to use as a field identification characteristic.

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.

In Southwest Desert Flora also see Lemmon's Ragwort, Senecio lemmonii, Threadleaf Ragwort, Senecio flaccidus var. flaccidus, Threadleaf Groundsel, Senecio flaccidus and Common Groundsel, Senecio vulgaris.

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

Importance to Wildlife, Birds and Livestock
Senecio flaccidus var. monoensis has large showy daisy-like flowers and the flowers and their seeds and plants may be visited by hummingbirds and/or small mammals including rodents and granivorous birds in search of food, nectar, shelter and protection through cover.

Beneficial Value to Butterflies, Bees and Insects
Senecio flaccidus var. monoensis has large showy daisy-like flowers and the flowers and their plants may be visited by butterflies, moths, native bees and other insects in search of nectar and/or other food.

daisy-like flowers, showy flowers

Etymology:
The genus “Senecio” (Sene'cio:) from senex, "old man," referring to the gray hairs on the seeds.

The genus Senecio was published in 1753 by Carl Linnaeus, (1707-1778).

The species epithet “flaccidus” (flac'cidus:) is Latin for flaccid.

Ethnobotany
Unknown

Date Profile Completed: 8/18/2012; updated 10/27/2020
References:
Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, as Senecio monoensis
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search; accessed 10/25/2020.
https://plants.usda.gov/core/profile?symbol=SEFLF
The Plant List (2013). Version 1.1. Published on the Internet; http://www.theplantlist.org/; accessed 10/25/2020.
http://www.theplantlist.org/1.1/browse/A/Compositae/Senecio/
Debra K. Trock 2012,flaccidus var. monoensis, in Jepson Flora Project (eds.) Jepson eFlora, /eflora/eflora_display.php?tid=8223, accessed on October 27, 2020.
Theodore M. Barkley † FNA | Family List | FNA Vol. 20 | Asteraceae; Senecio, 25c. Senecio flaccidus Lessing var. monoensis (Greene) B. L. Turner & T. M. Barkley, Phytologia. 69: 54. 1990.; Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
Kleiman, Russ, Dr., Associate Botanist, Dale A. Zimmerman Herbarium; Vascular Plants of the Gila Wilderness; Senecio flaccidus Lessing var. monoensis (Greene) B. Turner & T. Barkley (Threadleaf Groundsel); (accessed 10/27/2020) Presented in Association with the Western New Mexico University Department of Natural Sciences
https://wnmu.edu/academic/nspages/gilaflora/senecio_flaccidus_monoensis.html
Native Plant Information Network, NPIN (2013). Published on the Internet http://www.wildflower.org/plants/ [accessed: 10/27/2020]. Lady Bird Johnson Wildflower Center at The University of Texas, Austin, TX.
https://www.wildflower.org/plants/result.php?id_plant=SEFLM
Seiler, John, Peterson, John, North American species range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation
http://dendro.cnre.vt.edu/dendrology/
SEINet synonyms, scientific names, geographic locations, general information.
http://swbiodiversity.org/seinet/
Etymology:Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 10/24/2020)
http://www.calflora.net/botanicalnames/pageSA-SH.html
http://www.calflora.net/botanicalnames/pageF.html
IPNI (2020). International Plant Names Index. Published on the Internet http://www.ipni.org, The Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and Australian National Botanic Gardens. [Retrieved 25 October 2020].
https://www.ipni.org/?q=Senecio