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Montana Field Guides

Idaho Blue-eyed-grass - Sisyrinchium idahoense

Native Species

Global Rank: G5
State Rank: S4
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:
C-value: 6

External Links

State Rank Reason (see State Rank above)
Sisyrinchium idahoensis is present across a large area of western and central Montana. Plants populations can be locally common or scattered, and can be easily overlooked due to its stature and ability to grow with dense vegetation.
  • Details on Status Ranking and Review
    Idaho Blue-eyed-grass (Sisyrinchium idahoense) Conservation Status Review
    Review Date = 09/20/2016
    View State Conservation Rank Criteria
    Range Extent

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

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    Number of Populations

    ScoreD - 81 - 300

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

    ScoreD - Some (13-40) occurrences with excellent or good viability or ecological integrity

    Environmental Specificity

    ScoreB - Narrow. Specialist or community with key requirements common

    Long-term Trend

    ScoreU - Unknown


    ScoreU - Unknown


    ScoreU - Unknown

    CommentThreats: Unknown/undetermined.

    Intrinsic Vulnerability

    ScoreC - Not intrinsically vulnerable

General Description
Plants: Tufted perennial herbs with fibrous roots; stems typically simple (Cronquist et al. 1977) and flattened, to 45 cm in height (FNA 2002).

Leaves: Leaves firmly vertical or somewhat lax and ascending, usually not as tall as the stems (Cronquist et al. 1977), 1–2.5 mm in width; margins smooth to finely toothed (FNA 2002).

Inflorescence: Spathe usually borne at end of the stem, the bracts mostly very dissimilar in length (Cronquist et al. 1977); exterior bract 14-55(-65) mm in length (FNA 2002) with inside margins hyaline half the length or more, and base joining stem for (2)3.5-7(8) mm; interior bract 13-28(-33) mm in length with inside margins hyaline most of the bract’s length (Cronquist et al. 1977); inflorescence of usually 2-6 flowers subtended by delicate, smooth or glandular pedicels which seldom surpass the exterior bract (Cronquist et al. 1977).

Flowering May-August (Cronquist et al. 1977).

Diagnostic Characteristics
S. idahoense has an exterior bract that is usually joined at its base to the stem for more than 4 mm, and has slightly pitted seeds. The similar S. montanum’s exterior bract is usually connate at the base for less than 4 mm and the seeds coarsely pitted. The differences between the two species become muddled in various mountain ranges of Utah (Cronquist et al. 1977).

Fresh spathes and flowers provide the best characters for identification. Extreme care in pressing is required to prevent misidentification from marred characters (FNA 2002).

Species Range
Montana Range


Range Comments
BC, WA, ID and MT, s to CA, AZ, and NM. 0-7200 feet (FNA 2002).

Observations in Montana Natural Heritage Program Database
Number of Observations: 24

(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)

Streambanks (Cronquist et al. 1977), moist to wet, often saline or alkaline meadows; valleys, montane (Lesica 2012).

(Lesica’s contribution from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

Reproductive Characteristics
Flowers: Tepals 8–20 mm in length, blue with yellow bases (FNA 2002), conspicuously veined, oblanceolate or slightly elliptic with rounded or emarginate apices; anthers 1-2(2.5) mm tall, the filaments partially united to form a column around the style, the column 3-6.5 mm in height; ovary at time of flowering ranging from 1.4-3 mm in height, heavily covered in tiny glandular hairs (Cronquist et al. 1977).

Fruit: Capsule globose, 3–6 mm tall (Lesica 2012); seeds slightly pitted, 1-1.8 mm across (Cronquist et al. 1977).

(Lesica’s contribution adapted from Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX.)

  • Literature Cited AboveLegend:   View Online Publication
    • Cronquist, A., A. H. Holmgren, N. H. Holmgren, J. L. Reveal, and P. K. Holmgren. 1977. Intermountain flora: Vascular Plants of the Intermountain West, U.S.A. Volume 6: The Monocotyledons. New York, NY: Columbia University Press. 584 pp.
    • Flora of North America Editorial Committee. 2002. Flora of North America North of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. New York, NY: Oxford Univ. Press. xxvi + 723 pp.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
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Citation for data on this website:
Idaho Blue-eyed-grass — Sisyrinchium idahoense.  Montana Field Guide.  .  Retrieved on , from