Herrickia horrida
Author: Woot. & Standl.

Canadian River spiny aster

Asteraceae (sunflower family)

Close up of Herrickia horrida by Steve O'Kane.

Close up of Herrickia horrida by Steve O'Kane.
Close up of Herrickia horrida by Jill Handwerk.
Close up of Herrickia horrida by Jill Handwerk.

Taxonomic Comments

=Eurybia horrida (USDA NRCS 2017).

Ranks and Status

Global rank: G3
State rank: S1
Federal protection status: None
State protection status: None

Description and Phenology

Herrickia horrida by Carl Victor Stein

General description: Perennials or subshrubs, 3-6 dm tall. Leaves, oblong to nearly orbiculate, 1-5 cm long, thick, rigid, and the margins coarsely toothed with spine tips (holly-like). Flower heads about 10 mm high. Ray flowers purple, disk flowers yellow (Spackman et al. 1997, Ackerfield 2015).

Look Alikes: Easily recognized by its holly-like leaves (Weber and Wittmann 2012).

Phenology: Flowers July-October. Usually in prime flower in mid-August (Spackman et al. 1997).


Habitat of Herrickia horrida by Jill Handwerk.

Habitat of Herrickia horrida by Jill Handwerk.

In Colorado this species is found on rocky hillsides and on the sides of canyons, often with Gambel's oak, in dry sandy or rocky soils, and sometimes on almost bare sandstone bedrock.  Also found growing in pine duff in openings of Ponderosa pine-Gambel’s oak woodlands. Additional associated plant species: Mountain mahogany (Colorado Native Plant Society 1989, Weber and Wittmann 2012, Ackerfield 2015, Colorado Natural Heritage Program occurrence records 2017).

Elevation Range: 6,709 - 9,350 feet (2,045 - 2,850 meters)


Colorado endemic: No
Global range: South Las Animas County, Colorado and along the Canadian River drainage in Colfax, Harding, Mora, and San Miguel counties, New Mexico (USDA NRCS 2017).
State range: Known from Las Animas County in Colorado. Estimated range in Colorado is 48 square kilometers (19 square miles), calculated in GIS in 2008 by the Colorado Natural Heritage Program by drawing a minimum convex polygon around the known occurrences.
Distribution of Herrickia horrida in Colorado according to mapped land ownership/management boundaries (CNHP 2017, COMaP).

Distribution of Herrickia horrida in Colorado.

Threats and Management Issues

Summary results of an analysis of the status of Herrickia horrida based on several ranking factors. This species was concluded to be "Weakly Conserved”. From Rondeau et al. 2011.

Threats are not documented. Plants occurs on private land and on James M. John State Wildlife Area near Interstate 25 and the New Mexico border. Preferred habitat of species not suitable for development and very inaccessible. Some oil and gas drilling occurs within the vicinity of the occurrences with unknown impacts. Colorado climate scenarios for 2050 suggest temperature will increase by 3-7 F and precipitation may decrease or increase. The impact to any given rare plant habitat is likely to vary. Long-term monitoring that includes weather and soil moisture data is critical to understanding climate impacts.


    • Beardsley, M. and D. A. Steingraeber. 2013. Population dynamics, rarity and risk of extirpation for populations of Mimulus gemmiparus (budding monkeyflower) on National Forests of Colorado. A research report submitted to the USFS Forest Service. Arapaho and Roosevelt National Forets and Pawnee National Grassland. pp 17. Accessed online on May 11 at: http://www.r5.fs.fed.us/wildflowers/Rare_Plants/profiles/Critically_Imperiled/mimulus_gemmiparus/ documents/USFS_MimulusStatusReport2013.pdf
    • Colorado Natural Heritage Program and the Geospatial Centroid. 2017. The Colorado Ownership and Protection Map (COMaP). Colorado State University, Ft. Collins, CO.
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    • Weber, Johnston and Wilken. 1979. Additions to the flora of Colorado. Phytologia 41(7):490.
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