Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Xanthocephalum gymnospermoides, San Pedro Matchweed

Scientific Name: Xanthocephalum gymnospermoides
Common Name: San Pedro Matchweed
Also Called: Gummy Broomweed, Gummy Snakeweed, Matchweed
Family: Asteraceae, Sunflower Family
Synonyms: (Grindelia gymnospermoides, Gutierrezia gymnospermoides)
Status: Native
Duration: Annual
Size: Up to 4 feet more or less.
Growth Form: Forb/herb; plants with single stem with multiple branches in upper sections; herbage glabrous.
Leaves: Green; leaves up to 4 inches long; mostly lanceolate; margins entire or with small spiny teeth; leaf surface viscid or resinous.
Flower Color: Yellow, golden yellow; showy flower heads with both disk and short ray flowers, flower heads glutinous; multiple flower heads on each branch; fruit an achene.
Flowering Season: August to October in Arizona and July or August to October elsewhere.
Elevation: 1,000 to 5,500 feet.

Habitat Preferences: Meadows, stream bottoms, ditches and alluvial or often saline soil.

Recorded Range: Xanthocephalum gymnospermoides is rare in the United States although locally common where it is found only in AZ, TX. In Arizona it is found in Santa Cruz County and in Texas no locations are disclosed. Possibility that this species is also found in southwest New Mexico. A known record for this species from: San Diego, California, San Elijo Lagoon Conservation Reserve.

This species is also present in northern Mexico.

North America & US County Distribution Map for Xanthocephalum gymnospermoides.

U.S. Weed Information: No information available.
Invasive/Noxious Weed Information: No information available.

Wetland Indicator: In North America Xanthocephalum gymnospermoides, San Pedro Matchweed has the following wetland designations: Lower 48 States, FACW; North America, FACW; Arid West, FAC.
FACW = Facultative Wetland, usually occur in wetlands, but may occur in non-wetlands
FAC = Facultative, occur in wetlands and non-wetlands

Threatened/Endangered Information: No information available.

Genus Information: In North America there is 1 species and 1 accepted taxa overall for Xanthocephalum. World wide, The Plant List includes 7 accepted species names and includes a further 5 infraspecific rank for the genus.

In the Southwestern United States there is 1 species of Xanthocephalum. All data is approximate and subject to taxonomic changes.

Comments: Xanthocephalum gymnospermoides is rare in the United States found only in limited distribution in Arizona and Texas. The photos above are plants in Santa Cruz County, Arizona. Possibility that this species is also found in southwest New Mexico.

The type species for Xanthocephalum gymnospermoides is from between Babocomari, Arizona, and Santa Cruz, Sonora (Wright 1177)

Date Profile Completed: 12/05/2016, updated format 10/11/2017
Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, California.
U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search - (accessed 12/05/2016)
The Plant List (2013). Version 1.1. Published on the Internet; (accessed 12/05/2016).
Guy L. Nesom, FNA | Family List | FNA Vol. 20 | Asteraceae | Xanthocephalum; Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford.
Native Plant Information Network, NPIN (2013). Published on the Internet [accessed: ]. Lady Bird Johnson Wildflower Center at The University of Texas, Austin, TX.
SEINet synonyms, scientific names, geographic locations, general information - (accessed 12/05/2016).