Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Agoseris heterophylla, Annual Agoseris

Annual Agoseris has pretty yellow ligulate florets borne on single erects stems called “scapes”. This species blooms from March to May. Annual Agoseris readily attracts many species of insects, especially butterflies and moths. Agoseris heterophyllaAnnual Agoseris: The outer bracts or phyllaries, except the margins, are green or rosy purple, often darker spotted; note the phyllaries are lanceolate and may be either smooth or with slight pubescence. Agoseris heterophyllaAnnual Agoseris is also called Goatsbeard and Mountain Dandelion. This species is found in elevations from 2,500 to 5,000 feet is found in open areas in drier habitats in plains, mesas and canyons. Agoseris heterophylla Annual Agoseris has light green or greenish-whitish basal rosette leaves, a narrow leaf about 6 inches long and a half inch wide. The leaves have entire margins, toothed and with a variable white-hairy pubescence overall. Agoseris heterophylla

Scientific Name: Agoseris heterophylla
Common Name: Annual Agoseris
Also Called: Annual Goatsbeard, Mountain Dandelion
Family: Asteraceae, Sunflower Family
Synonyms: (Troximon chilense, Troximon heterophyllum)
Status: Native
Duration: Annual
Size: Up to 16 inches in form of a flowering stalk (peduncle) or scape.
Growth Form: Forb/herb; erect, small dandelion-like plant covered in small white-hairy pubescence; milky sap.
Leaves: Light green or greenish-whitish, basal rosette leaves, about 6 inches long and narrow, about ½ inch wide, leaf shape variable, narrow, oblanceolate; margins entire, dentate or pinnatifid; variable white-hairy pubescence overall.
Flower Color: Yellow; ligulate florets only, heads solitary borne on single erect stem, several stems from the base; phyllaries are green or rosy-purple (except the margins), and sometimes darker spotted and/or tipped, phyllaries are lanceolate to obovate, glabrous or pubescent; fruit is an achene, pappus of white bristles like a dandelion.
Flowering Season: March to May.

Elevation: 2,500 to 5,000 feet.
Habitat Preferences: Open areas in higher elevations, drier habitats in the plains, mesas and canyons in Arizona.

Recorded Range: Agoseris glauca is found in the western United States and British Columbia: In the United States in AZ, CA, CO, ID, MT, NM, NV, OR, UT and WA.

North America & US County Distribution Map for Agoseris heterophylla.

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 10 species and 10 accepted taxa overall for Agoseris. World wide, The Plant List includes 15 accepted species names and includes a further 72 of infraspecific rank for the genus. Common names for this genus are Mountain Dandelion and False Dandelion.

In the Southwestern United States: Arizona and New Mexico each have 3 species of Agoseris, California has 7 species, Nevada has 6 species, Texas has 0 species, Utah has 5 species. All data is approximate and subject to taxonomic changes.

Comments: Annual Agoseris is not a desert species. It belongs to a small genus of plants with rosette leaves and resembling the common dandelion with their similar yellow flowers and puff ball seed heads. Adding to confusion are the common names for Agoseris such as Mountain- and False-Dandelion. (See Common Dandelion, Taraxacum officinale.

Annual Agoseris is one of three species of Agoseris native to Arizona which also includes Pale Agoseris, Agoseris glauca, and Orange Agoseris, Agoseris aurantiaca.

Date Profile Completed: 6/5/2013; Updated, 07/25/2015, updated 09/05/2017
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 09/04/2017)
The Plant List (2013). Version 1.1. Published on the Internet; (accessed 09/04/2017).
Gary I. Baird 2017. Agoseris heterophylla, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on September 05, 2017.
Gary I. Baird, FNA | Family List | FNA Vol. 19, 20 and 21 | Asteraceae | Agoseris, Page 323, 324, 331, 332, Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford. (accessed 09/04/2017)
SEINet synonyms, scientific names, geographic locations, general information, (accessed 09/04/2017).