Southwest Colorado Wildflowers, Gutierrezia sarothrae

Gutierrezia microcephala and Gutierrezia sarothrae are widespread through the semi-desert areas of the Four Corners. Gutierrezia microcephala is found only in the very southwest corner of the U. S. from far west Texas to southern California and from the very southwest corner of Colorado to central Nevada. Gutierrezia sarothrae is found in the same area and also farther north through all the western states and into Canada. The two are often in the company of that other ubiquitous Westerner, Sagebrush.

Gutierrezia microcephala and Gutierrezia sarothrae often grow in extensive patches, especially at road side and on grazed land where they tend to multiply because cattle dislike them.

Gutierrezia microcephala and Gutierrezia sarothrae are quite similar and one needs a bit of determination and a hand lens to tell the difference between the two. Both grow in the same environment, often right next to each other; both have minute flowers; both have the same rounded appearance and grow to the same height of one to three feet; both flower in late summer and fall. The most easily observed difference is in the flowers: G. microcephala has only one or two of both ray and disk flowers; G. sarothrae has three to seven ray and disk flowers.

Mariano Lagasca named this genus for Pedro Gutierrez, a 19th century botanist with the Botanical Garden of Madrid. (More biographical information.) "Microcephala" is Greek for "small head" and "sarothrae" is from the Greek for "broom".

Click for more Gutierrezia photographs.

Gutierrezia microcephala (Broom Snakeweed)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Openings, roadsides. Summer, fall.
Butler Canyon, Utah, August 27, 2007.

Flowers are crowded at the top of very slender stems. The plant grows along trails, at roadsides, in sandy and rocky areas, and in pastures.

G. microcephala was first named Brachyris microcephala by Augustin de Candolle in 1836 from a collection made by Berlandier in Mexico. Asa Gray renamed the plant Gutierrezia microcephala in 1849.

Gutierrezia microcephala (Broom Snakeweed)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Openings, roadsides. Summer, fall.
Butler Canyon, Utah, August 27, 2007.

Notice all the single ray flowers. I at first thought that the other ray flowers had dropped and that I was looking at G. sarothrae. This plant also has only one disk flower per head.

Leaves are very similar to those of G. sarothrae: 2-5 centimeters long and 2-4 millimeters wide.

Gutierrezia sarothrae (Broom Snakeweed)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Openings, roadsides. Summer, fall.
Big Spring Trail, Canyonlands National Park, Utah, September 10, 2005.

Lower leaves on both species of Gutierrezia are often withered at flowering time. Flowers are clustered tightly at the top of the plant.

Gutierrezia sarothrae was first collected for science by Meriwether Lewis along the Missouri River in 1804 and was named Solidago sarothrae by Pursh in 1814. It was renamed Gutierrezia sarothrae by Britton and Rusby in 1887.

Gutierrezia sarothrae (Broom Snakeweed)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Openings, roadsides. Summer, fall.
Big Spring Trail, Canyonlands National Park, Utah, September 10, 2005.
Butler Canyon, Utah, August 27, 2007.

Flowers often do not look as uniform and symmetrical as shown at left. The photograph below shows varying stages of development: the flower cluster at top left has both ray and disk flowers; the two largest flower clusters below that one have only disk flowers. What appear to be rays on the disk flowers are just lobes on the flower tube.

Gutierrezia sarothrae (Broom Snakeweed)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Openings, roadsides. Summer, fall.
Butler Canyon, Utah, August 27, 2007.

Leaves are 2-7 centimeters long and 1-3 millimeters wide.