Carnegiea gigantea, Giant Saguaro

Southwest Desert Flora

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

Cirsium ochrocentrum, Yellowspine Thistle

Almutaster pauciflorus, Alkali Marsh Aster

Alkali Marsh Aster has purple, lavender or whitish medium sized showy flowers with anywhere from 3 to 10 floral heads per plant. These daisy-type flowers are called radiate meaning they have both ray and disk florets included in the head. Almutaster pauciflorus Alkali Marsh Aster flowers somewhat glandular phyllaries (bracts surrounding floral parts) as shown in the photo. Almutaster pauciflorus Alkali Marsh Aster grows from 12 to 47 inches (30-120 cm) tall depending on the locality. Plants bloom from May to September, June to October in California and prefer elevations from 650 to 7,800 feet (200–2400 m), again depending on locality. Almutaster pauciflorus Alkali Marsh Aster grows has large green leaves that generally have smooth margins. Note in the photo that the basal leaves are more linear and the leaves higher up on the stem are narrowly spatulate. Almutaster pauciflorus

Scientific Name: Almutaster pauciflorus
Common Name: Alkali Marsh Aster

Also Called: Alkalai Marsh Aster, Alkali-marsh Aster, Alkalimarsh Aster, Marsh-Aster

Family: Asteraceae, Sunflower Family

Synonyms: (Aster pauciflorus, Aster hydrophilus, Tripolium pauciflorum)

Status: Native

Duration: Perennial for a rhizome.

Size: 12 to 47 inches (30-120 cm).

Growth Form: Forb/herb; partially colonial; plants upright (erect) to spreading horizontally, then becoming erect (ascending), stems reddish-green, becoming hairless, upper stems glandular-pubescent.

Leaves: Green; lower leaves linear, with short supporting stalk; upper leaves without supporting stalk, wider and glandular; leaf edges (margins) generally smooth.

Flower Color: Purple, lavender or whitish, flowers showy, daisy-like, 3 to 10 heads on branch tips; floral heads with both ray and disk florets; bracts surrounding heads broadly linear and glandular.

Flowering Season: May to September, June to October in California.

Elevation: 650 to 7,800 feet (200–2,400 m) depending on locality.

Habitat Preferences: alluvial and alkaline soil, often found in salty areas with halophytic vegetation, along streams, ditches, desert and dry prairie areas, inland salt marshes.

Recorded Range: Almutaster pauciflorus is found from northern Canada (Northwest Territories), Alberta, Saskatchewan, Manitoba southward into the United States through North Dakota, South Dakota, Montana, Wyoming southward through the southwestern United Stated and south into northern and central Mexico; in California this species is found in the Mojave Desert.

North America & US County Distribution Map for Almutaster pauciflorus.

North America species range map for Alkali Marsh Aster, Almutaster pauciflorus:
North American range map courtesy of Virginia Tech, Dept. of Forest Resources & Environmental Conservation

North America species range map for Almutaster pauciflorus: Click image for full size map
Click image for full size map

U.S. Weed Information: Unknown
Invasive/Noxious Weed Information: Unknown

Wetland Indicator: In North America Almutaster pauciflorus has the following wetland designations:

  • Arid West, FACW;
  • Great Plains, FACW;
  • Western Mountains, Valleys, and Coast, FACW.

  • FACW = Facultative Wetland, usually occur in wetlands, but may occur in non-wetlands

    Threatened/Endangered Information: In North America Almutaster pauciflorus is listed in The California Native Plant Society (CNPS) Rare and Endangered Plant Inventory; California Rare Plant Rank: 2B.2 - Rare or Endangered in California, common elsewhere. 2: Fairly endangered in California

    Genus Information: In North America, and world-wide, according to The Plant List, there is 1 species and 1 accepted taxa overall for Almutaster.

    The genus Almutaster was published in 1982 by Askell Love and Doris Benta Maria Love.

    Comments: Arizona locations: San Bernardino Ranch and valley of the San Pedro River (Cochise County); Santa Cruz River valley and Aqua Caliente (Pima County)

    In Southwest Desert Flora also see superficially similar looking species Mesa Tansyaster, Machaeranthera tagetina, Tansyleaf Tansyaster, Machaeranthera tanacetifolia and Hoary Tansyaster, Xylorhiza tortifolia.

    Importance to Wildlife, Birds and Livestock
    Alkali Marsh Aster, Almutaster pauciflorus, Alkali Marsh Aster, daisy-like brightly colored flowers, seeds and plants may likely be eaten by birds and small mammals.

    Special Value to Native Bees, Butterflies and Insects
    Daisy type flowers such as Alkali Marsh Aster may be visited by butterflies, bees and other small insects.
    The genus Almutaster honors American Aster expert Almut Gitter Jones (Mrs. George Neville Jones - 1923-2013), American botanist and plant systematist.

    The genus Almutaster was published in 1982 by Askell Love and Doris Benta Maria Love.

    The species epithet "pauciflorus" means few-flowered.


    Date Profile Completed: 01/13/2021
    Kearney, Thomas H., Peebles, Robert H., 1960, Arizona Flora, University of California Press, Berkley and Los Angeles, California; as Aster pauciflorus
    U.S. Dept. of Agriculture, Natural Resources Conservation Service on-line database and USGS ITIS search - (accessed 01/27/2020)
    The Plant List (2013). Version 1.1. Published on the Internet; (accessed 01/27/2020).
    Luc Brouillet; Flora of North America North of Mexico |FNA | Family List | FNA Vol. 20 | Asteraceae | Almutaster 1. Almutaster pauciflorus (Nuttall) Á. Love & D. Love, Taxon. 31: 356. 1982.; Marsh alkali aster (accessed 00/00/2000).
    John C. Semple 2012, Almutaster pauciflorus, in Jepson Flora Project (eds.) Jepson eFlora, eflora_display.php?tid=12710, accessed on January 27, 2020.
    Alkali Marsh Aster — Almutaster pauciflorus. Montana Field Guide. Montana Natural Heritage Program. Retrieved on January 27, 2020,
    'Almutaster', Wikipedia, The Free Encyclopedia, 22 August 2019, 13:45 UTC, [accessed 28 January 2020]
    California Native Plant Society (CNPS) Rare and Endangered Plant Inventory (accessed January 27, 2020)
    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 01/28/2020)