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Green-band Mariposa Lily - Calochortus macrocarpus

Native Species

Global Rank: G5
State Rank: S3S4
(see State Rank Reason below)

Agency Status


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State Rank Reason (see State Rank above)
Calochortus macrocarpus occurs in northwestern Montana where it occupies mesic grasslands, meadows, and pine woodlands with volcanic-derived soils. Plants are palatable to livestock and habitat has been cultivated which led to a report of it slowly declining in the northwestern portion of the Intermountain Region (Cronquist et al. 1977). In the Flathead region of Montana, plants can be common in the grasslands, but there are threats to the quality of habitat, particularly from exotic plants. Plants require several years to reach reproductive maturity. Current data on population sizes and trends, distribution, and threats is greatly needed before re-examining if a Species of Concern status is warranted.
  • Details on Status Ranking and Review
    Green-band Mariposa Lily (Calochortus macrocarpus) Conservation Status Review
    Review Date = 08/03/2020
    View State Conservation Rank Criteria
    Range Extent

    ScoreE - 5,000-20,000 sq km (~2,000-8,000 sq mi)

    Comment9,163 square kilometers.

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    CommentMontana can be divided into 30,390 4x4 square kilometer cells. For this species plant observations occur in 20 of these 4x4 square kilometer cells.

    Number of Populations

    ScoreC - 21 - 80

    Comment23 discrete observations.

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

    ScoreC - Few (4-12) occurrences with excellent or good viability or ecological integrity

    Comment5 observations assumed of good viability based on descriptors of 'locally common', 'common', or 'abundant'.


    ScoreD - Low

    CommentPlants are palatable to livestock and noted as declining in Cronquist et al. 1977 publication. Invasive species and quality habitat are also a threat.

    Intrinsic Vulnerability

    ScoreB - Moderately vulnerable

General Description
PLANTS: Herbaceous perennial plants that grow from bulbs. Stems are usually single and 20-50 cm tall. Source: Lesica et al. 2012.

LEAVES: Few, basal and alternately arranged on stem. Basal leaves are narrow (1-2 mm), channeled or inrolled, and usually shorter than stem leaves. Sources: Lesica et al. 2012; Giblin et al. [eds.] 2018.

INFLORESCENCE: Terminal, of 1 to 4 stemmed (pedicellate), purplish flowers. Bracts are 3-10 cm long. 3 sepals alternate with 3 petals. Sepals are narrow, often longer than petals, purplish, and 3-6 cm long. Petals purple, acuminate, and 3-5 cm long; outer surface with a green midvein; inner surface with an ovate, yellow-fringed gland and a crescent-shaped purple mark above. Sources: Lesica et al. 2012; Giblin et al. [eds.] 2018.

Montana's plants are of variety macrocarpus (Fiedler and Zebell in Flora of North America [FNA] 2002).

The genus, Calochortus, comes from the Greek words kalos meaning 'beautiful' and chortos meaning 'grass' (Fiedler and Zebell in FNA 2002).

Flowering late spring to mid-summer (Fiedler and Zebell in FNA 2002).

Diagnostic Characteristics
Green-band Mariposa Lily - Calochortus macrocarpus
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Lanceoloid (round in cross-section; wider from base to below middle then tapering to the tip).
*Sepals: Usually longer than petals.
*Petals: Purple. Green striped on the outside. Tip acuminate.

Nuttall's Mariposa Lily - Calochortus nuttallii
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Oblong.
*Sepals: Longer or shorter than petals.
*Petals: White to purple tinged, yellow at the base. Lacking a green stripe on the outside. Bearded on the inside, adjacent to gland. Tip apiculate.

Bruneau Mariposa Lily - Calochortus bruneaunis, SOC
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Oblong.
*Sepals: Usually shorter than petals.
*Petals: White. Green striped on the outside. Nearly hairless on the inside (glabrate) near gland. Tip apiculate.

Gunnison's Mariposa Lily - Calochortus gunnisonii
*Basal Leaf: Channeled, similar in width, but shorter than stem leaves.
*Anthers: Apiculate (short, sharp tip).
*Sepals: Usually shorter than petals.
*Petals: White or yellowish to purple; greenish inside and sometimes purple-banded or -spotted next to gland. Green stripe absent on the outside. Tip not acuminate.

The following Mariposa Lilies differ from those above in that their basal leaves are flat, much wider than the stem leaves, and often more than half as long as the stem leaves:

Baker Mariposa Lily - Calochortus apiculatus
Elegant Mariposa Lily - Calochortus elegans
Big-pod Mariposa Lily - Calochortus eurycarpus

Species Range
Montana Range Range Descriptions


Range Comments
British Columbia, Montana south to California and Nevada (Lesica et al. 2012).

Observations in Montana Natural Heritage Program Database
Number of Observations: 25

(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)

Grasslands and pine woodlands in the valley zone of Montana (Lesica et al. 2012).

For Calochortus, petal size can vary between years and may be associated with soil moisture (Lesica et al. 2012).

Reproductive Characteristics
Plants reproduce from seed.

Most species propagate easily from seeds (Giblin et al. [eds.] 2018). It takes from 3-5 years to grow from seed to a flowering bulb (Giblin et al. [eds.] 2018). Bulbs collected in the wild rarely survive when planted (Giblin et al. [eds.] 2018).

Petals: 3, distinct, and purplish with an acuminate tip. At the base of the petal is a gland.
Gland: oblong-oval, more or less sagittate at the base, bordered with a mostly continuous fringed membrane, and has a surface covered with elongate, branched, thick hairs.
Stamens: 6, anthers are lanceoloid and longer than the filaments.
Pistil: Single with a 3-lobed style.

Fruit is a capsule. Capsule is spindle-shaped, erect, 4-5 cm long, and filled with many seeds. Ovary and capsules elongate greatly with age (longer than thick) and are not winged (Giblin et al. [eds.] 2018).

Threats or Limiting Factors
In Montana plants are threatened by changes to the habitat from invasion of exotic plants.

  • 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.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Cope, M.G. 1992. Distribution, habitat selection and survival of transplanted Columbian Sharp-tailed Grouse (Tympanuchus phasianellus columbianus) in the Tobacco Valley, Montana. M.Sc. Thesis. Bozeman, Montana: Montana State University. 60 p.
    • 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.
    • Quire, R.L. 2013. The sagebrush steppe of Montana and southeastern Idaho shows evidence of high native plant diversity, stability, and resistance to the detrimental effects of nonnative plant species. M.Sc. Thesis. Bozeman, MT: Montana State University. 124 p.
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Citation for data on this website:
Green-band Mariposa Lily — Calochortus macrocarpus.  Montana Field Guide.  .  Retrieved on , from