Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Senecio lemmonii, Lemmon's Ragwort

Lemmon's Ragwort has showy bright yellow flowers that bloom from February to May or later with sufficient monsoon rainfall. Lemmon’s Ragwort is similar superficially in appearance to Threadleaf Ragwort and Smooth Threadleaf Ragwort. Senecio lemmonii Lemmon's Ragwort is of the genus Senecio which as a group have similar characteristics found in the phyllaries surrounding the “flower” head. One characteristic, visible but difficult to see in the photo, is the black or dark spots on the pointed tips of the phyllaries. Senecio lemmonii Lemmon's Ragwort is similar to several other Ragwort species however the shape of the leaf including the clasping leaf bases and the axillary tufts of hair help separate various species. Shown in this photograph are the clasping dentate leaf bases. Senecio lemmonii Lemmon's Ragwort is rare in the United States where it is native only to the central and southern parts of Arizona. Its preferred habitats include rocky slopes and dry hillsides usually among shrubs. It grows in elevations from 1,500 to 3,500 feet. Senecio lemmonii

Scientific Name: Senecio lemmonii
Common Name: Lemmon's Ragwort
Also Called: Lemmon Groundsel
Family: Asteraceae, Sunflower Family
Synonyms: (Senecio decorticans)
Status: Native
Duration: Perennial
Size: Up to 3 feet or more.
Growth Form: Forb/herb, subshrub; erect or ascending; stems and leaves mostly glabrous.
Leaves: Green; leaves, up to 4 inches long; alternate; lanceolate to lance-linear; upper leaves sessile or clasping, auriculate; margins unevenly dentate; leaves with tufts of white hairs in leaf axils.
Flower Color: Yellow; 4 to 12 flowers in campanulate involucre; radiate heads about an inch or more wide; ray florets, disk florets orange-yellow; phyllaries tips with minute black dots; fruit an achene.
Flowering Season: February to May.
Elevation: 1,500 to 3,500 feet.

Habitat Preferences: Rocky slopes, dry hillsides, usually among shrubs.

Recorded Range: Lemmon's Ragwort is a relatively rare plant in the United States where it is found only in Arizona in the central and southern parts of the state as well as Yuma and Navajo Counties. It is also native to Baja California.

North America & US County Distribution Map for Senecio lemmonii.

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.

Comments: Lemmon's Ragwort is an early spring bloomer that is common in Arizona in preferred habitats. Photo above taken April 12 near the Salt River along the Apache Trail, Fish Creek Hill, Maricopa County, Arizona. The type of Senecio decorticans is from along the Salt River, near the Apache Trail (Nelson 10309, 11287).

Lemmon's Ragwort looks similar to several other Ragworts howver the shape of the leaf including the clasping leaf bases and the axillary tuft of hair help separate various species.

The genus Senecio is derived from the latin root senex meaning "old" or seneció for "old man" referring to the gray hairs on the seeds. Lemmonii is in honor of John Gill Lemmon (1832-1908) an American botanist, Civil War veteran and former prisoner of Andersonville. John G. Lemmon was married to fellow botanist, Sara Plummer Lemmon, and the two jointly cataloged numerous western and desert plants.

In Southwest Desert Flora also see Threadleaf Ragwort, Senecio flaccidus var. flaccidus and Smooth Threadleaf Ragwort, Senecio flaccidus var. monoensis and Common Groundsel, Senecio vulgaris.

Date Profile Completed: 10/27/2012; Updated, 07/26/2015, updated format 10/11/2017
Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles.
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search - (accessed 05/05/2017)
Hosch, William L., Feb 15, 2008; The Editors of Encyclopædia Britannica; Access Date: May 05, 2017
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.
SEINet for synonyms, scientific names and recorded geographic locations, [accessed: DATE 05/07/2017].
Wikipedia contributors, 'John Gill Lemmon', Wikipedia, The Free Encyclopedia, 21 January 2017, 21:23 UTC, [accessed 8 May 2017]
Wiktionary contributors, 'senecio', Wiktionary, The Free Dictionary, 8 November 2016, 22:26 UTC, [accessed 8 May 2017]