Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Xanthisma spinulosum, Lacy Tansyaster

Lacy Tansyaster has bright yellow flowers with both ray and disk florets. Note kissing bug on ray florets. Xanthisma spinulosum Lacy Tansyaster bracts surrounding floral heads are narrowly linear as shown here. The fruit is a cypsela and the seed is hairy for wind distribution. Xanthisma spinulosum Lacy Tansyaster has green or gray green leaves. The blades are variable in shape. Xanthisma spinulosum Lacy Tansyaster blooms from March to October and prefers elevations from 2,000 to 5,000 feet (610-1,524 m). Xanthisma spinulosum Lacy Tansyaster is found in the lower and upper desert communities, pinyon-juniper and chaparral habitats, sunny open areas, rocky, sandy and gravelly areas. Xanthisma spinulosum

Scientific Name: Xanthisma spinulosum
Common Name: Lacy Tansyaster

Also Called: Cutleaf Goldenweed, Cutleaf Ironplant, Ironplant, Lacy Tansy-aster, Pinnate Machaeranthera, Spiny Goldenweed, Spiny Haplopappus

Family: Asteraceae, Sunflower Family

Synonyms: (Amellus spinulosus, Aploppus spinulosus, Aster pinnatifidus, Dieteria spinulosa, Diplopappus pinnatifidus, Eriocarpum spp, Haplopappus spp, Machaeranthera autralis, Machaeranthera pinnatifida var. gooddingii, Machaeranthera texensis, Sideranthus australis, Starkea pinnata, more)

Status: Native

Duration: Perennial from a taproot.

Size: Up to 3 feet (91 cm) tall or more.

Growth Form: Forb/herb, subshrub; bases typically woody; plants upright or spreading; stems 1 to numerous; plants stout; stems variable from hairless to matted with woolly hairs; may be glandular hairy.

Leaves: Green, gray-green; lower basal leaves withered by flowering; blades variable; leaves hairy or hairless; may be glandular hairy.

Flower Color: Yellow; flora heads with both ray and disk florets; bracts or phyllaries surrounding floral heads narrowly linear as shown above; fruit is a cypsela, and the seeds have a feathery or hairy top for greater wind distribution.

Flowering Season: March to October

Elevation: 2,000 to 5,000 feet (610-1,524 m)

Habitat Preferences: Lower and upper (piñon, juniper) desert communities, pinyon-juniper and chaparral habitats, sunny open areas, arid grasslands, rocky, sandy and gravelly areas.

Recorded Range: Throughout southwestern and central United States west of the Mississippi River and central Canada. Also recorded in Baja California and northern Mexico. Found throughout Arizona.

North America & US County Distribution Map for Xanthisma spinulosum as Machaeranthera pinnatifida.

North America species range map for Lacy Tansyaster, Xanthisma spinulosum:

Lacy Tansyaster, Xanthisma spinulosum: Click image for full size map
Click image for full size map

U.S. Weed Information: Xanthisma spinulosum is listed in: Weeds of Nebraska and the Great Plains. Plants included here may become weedy or invasive.

Wetland Indicator: In North America Xanthisma spinulosum has the following wetland designations:

  • Arid West, UPL
  • Atlantic and Gulf Coastal Plain, FACU;
  • Great Plains, UPL;
  • Midwest, FACU;
  • Western Mountains, Valleys, and Coast, FACU;

  • FACU = Facultative Upland, usually occur in non-wetlands, but may occur in wetlands
    UPL = Obligate Upland, almost never occur in wetlands
    Invasive/Noxious Weed Information: Unknown
    Threatened/Endangered Information: Unknown

    Genus Information: In North America there are 18 species and 18 accepted taxa overall for Machaeranthera. Worldwide, The Plant List includes 27 accepted species names and a further 18 scientific names of infraspecific rank for Machaeranthera.

    The genus Machaeranthera was published in 1832 by Christian Gottfried Daniel Nees von Esenbeck (1776-1858).

    The synonym genus Xanthisma was published by Augustin Pyramus de Candolle in 1836.

    In the Southwestern United States: Arizona and New Mexico each have 13 species of genus, California, Nevada, Texas and Utah each have 8 species. Data approximate, subject to revision.

    There are 5 varieties in Xanthisma spinulosum in Flora of North America;
    Xanthisma spinulosum var. gooddingii (AZ,CA,NV);
    Xanthisma spinulosum var. paradoxum (CO,NM,UT);
    Xanthisma spinulosum var. glaberrimum (CO,IA,KS,NE,NM,OK,TX,WY) ;
    Xanthisma spinulosum var. spinulosum (USA; Central mid-west, and Canada: AB,SK,MB);
    Xanthisma spinulosum var. chihuahuanum (AZ,NM,TX);

    Comments: The yellow daisy-like flowered species are often included in Machaeranthera. Lacy Tansyasters have variable characteristics and are taxonomically confusing to botanists as evidenced with the many taxonomic changes over the years. Its true classification may yet be resolved.

    Also see in Southwest Desert Flora the very similar but annual species, Slender Goldenweed, Xanthisma gracilis.

    Importance to Wildlife, Birds and Livestock
    Lacy Tansyaster, Xanthisma spinulosum, has showy, daisy-like flowers, the flowers, their seeds and plants may be visited by hummingbirds and/or small mammals including rodents and granivorous birds in search of food, nectar and protection through cover.

    Beneficial Value to Butterflies, Honey Bees and Insects
    Lacy Tansyaster, Xanthisma spinulosum, has showy, daisy-like flowers, the flowers and their plants may be visited or used by butterflies, moths, flies, honeybees, native bees and other insects in search of nectar, food or shelter and protection.

    The genus “Machaeranthera” (Machaeran'thera:) is Greek for sword-like anthers. The genus Machaeranthera was published by Christian Gottfried Daniel Nees von Esenbeck in 1832.

    The genus Machaeranthera was published in 1832 by Christian Gottfried Daniel Nees von Esenbeck (1776-1858).

    The synonym genus Xanthisma (Xanthis'ma:) is a Greek name meaning "that which is dyed yellow," in reference to the flowers.

    The genus Xanthisma was published by Augustin Pyramus de Candolle in 1836.

    The species epithet spinulosum (spinos'um:) is Latin for "thorny" which suits this species very well.


    Date Profile Completed: 8/11/2012; updated 12/30/2020
    Arizona Flora, Kearney, Thomas H., Peebles, Robert H., 1960, University of California Press, Berkley and Los Angeles, as Aploppus spinulosus.
    U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search; accessed 12/30/2020 - as Machaeranthera pinnatifida
    The Plant List (2013). Version 1.1. Published on the Internet;; accessed 12/29/2020.
    Ronald L. Hartman, FNA | Family List | FNA Vol. 20 | Asteraceae - Xanthisma; 8. Xanthisma spinulosum (Pursh) D. R. Morgan & R. L. Hartman, Sida. 20: 1406. 2003.; 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 12/18/2020. Lady Bird Johnson Wildflower Center at The University of Texas, Austin, TX.
    FNA 2006, Allred and Ivey 2012; Editors: S.Buckley 2010, F.S.Coburn 2014, A.Hazelton 2017; from SEINet Field Guide, on-line; accessed 12/30/2020.
    Seiler, John, Peterson, John, North American species range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation
    SEINet synonyms, scientific names, geographic locations, general information.
    Etymology:Michael L. Charters California Plant Names: Latin and Greek Meanings and Derivations; A Dictionary of Botanical and Biographical Etymology - (accessed 12/25/2020 and 12/30/2020)
    IPNI (2020). International Plant Names Index. Published on the Internet, The Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and Australian National Botanic Gardens. [Retrieved 29 December 2020].