Search Field Guide
Advanced Search
MT Gov Logo
Montana Field Guide

Montana Field Guides

Large-flower Agoseris - Agoseris grandiflora

Native Species

Global Rank: G5
State Rank: S2S4
(see State Rank Reason below)

Agency Status


External Links

State Rank Reason (see State Rank above)
Agoseris grandiflora occurs in western Montana where it is documented from less than a dozen widely scattered locations. Agoseris grandiflora has long been recognized as occurring in Montana (Booth 1966), but after the Vascular Plants of Montana (Dorn 1984) was published, a closely related look-alike, Agoseris parviflora was recognized in our State. Therefore, older field reports of Agoseris grandiflora could actually be mis-identified. Agoseris grandiflora grows in commonly found habitats where threats have not been identified, yet most observation data is old. Current population and mapping data that captures abundance, viability, threats, and habitat needs on accurately identified plants are greatly needed to assess its status.
  • Details on Status Ranking and Review
    Large-flower Agoseris (Agoseris grandiflora) Conservation Status Review
    Review Date = 09/10/2020
    View State Conservation Rank Criteria
    Range Extent

    ScoreF - 20,000-200,000 sq km (~8,000-80,000 sq mi)

    Comment24,566 square kilometers for 12 observations.

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    CommentMontana can be divided into 30,390 4x4 square kilometer cells. For this species 12 plant observations occur in 11 of these 4x4 square kilometer cells.

    Number of Populations

    ScoreB - 6 - 20

    Comment12 observations.

    Number of Occurrences or Percent Area with Good Viability / Ecological Integrity

    CommentOne observation is assumed to be of good viability based on descriptor of 'common'.

    Environmental Specificity

    ScoreC - Moderate. Generalist or community with some key requirements scarce


    CommentThreats are not identified.

General Description
PLANTS: Perennial herbs that grow 25 to 60 cm tall from a taproot. Source: Lesica et al. 2012

LEAVES: Basal leaves are 10–25 cm long, linear-oblanceolate in outline and lobed more than half-way to their midvein (deeply pinnatifid). Hairs are sparse (glabrate) or are long, soft, crooked and un matted (villous). Source: Lesica et al. 2012

INFLORESCENCE: A solitary, yellow flowerhead. The involucre is 2–4 cm high with the bracts (phyllaries) arranged in 4 to 5 rows (series). Each involucral bract is green, villous on the margin, and centrally purplish. Ray petals are yellow and 3–7 mm long. Pappus is 7–15 mm long. Achene (fruit) body is 3–7 mm long and beak is 9–16 mm long. Source: Lesica et al. 2012

Agoseris comes from the Greek words of agos meaning 'leader' and seris meaning 'chicory', but what this refers to is unclear (Baird in Flora of North America [FNA] 2006).

Diagnostic Characteristics
Agoseris species in Montana share the following characteristics:
*Solitary flowerhead composed only of ray (ligulate) flowers; each ray tipped with 5 lobes.
*Single, long flowering stem (peduncle) that has milky sap;
*Leaves are only basal; each leaf with a simple blade that tapering to the stem (petiole).

Large-flower Agoseris - Agoseris grandiflora
*Life Span: Perennial
*Flowers (Corollas): Yellow
*Leaf Blades: Lobes divided half-way to the midvein.
*Involucral Bracts: Villous on the margins.
*Achene Beak: At least 8 mm long.

Steppe Agoseris - Agoseris parviflora
*Life Span: Perennial
*Flowers (Corollas): Yellow
*Leaf Blades: Lobes divided half-way to the midvein.
*Involucral Bracts: Glabrous or tomentose.
*Achene Beak: Less than 6 mm long.

Pale Agoseris - Agoseris glauca
*Life Span: Perennial
*Flowers (Corollas): Yellow
*Leaf Blades: Entire or with shallow lobes that are less than half-way to the midvein.

Annual Agoseris - Agoseris heterophylla
*Life Span: Annual
*Flowers (Corollas): Yellow
*Leaf Blades: Not lobed; entire to slightly dentate.

Orange Agoseris - Agoseris aurantiaca
*Life Span: Perennial
*Flowers (Corollas): Orange to pink, often drying light purple
*Leaf Blades: Entire, dentate, or with shallow lobes.

Species Range
Montana Range Range Descriptions


Range Comments
Agoseris is a New World genus meaning that all species occur in North America (Baird in FNA 2006). However, there is an exception for one species that is found in the temperate regions of southern South America (Baird in FNA 2006).

Large-flower Agoseris occurs in British Columbia and Montana south to California, Nevada, and Utah (Baird in FNA 2006); Lesica et al. 2012).

Observations in Montana Natural Heritage Program Database
Number of Observations: 10

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Meadows within forests in the valley and montane zones of Montana (Lesica et al. 2012).

The following animal species have been reported as pollinators for this plant species or genus
where their geographic ranges overlap: Bombus bifarius and Bombus insularis (Wilson et al. 2010).

  • Literature Cited AboveLegend:   View Online Publication
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Wilson, J.S., L.E. Wilson, L.D. Loftis, and T. Griswold. 2010. The montane bee fauna of north central Washington, USA, with floral associations. Western North American Naturalist 70(2): 198-207.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
  • Web Search Engines for Articles on "Large-flower Agoseris"
Login Logout
Citation for data on this website:
Large-flower Agoseris — Agoseris grandiflora.  Montana Field Guide.  .  Retrieved on , from