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Montana Field Guides

Leafy Bentgrass - Agrostis pallens
Other Names:  Agrostis diegoensis

Native Species

Global Rank: G4G5
State Rank: S3S4
(see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 6

External Links






State Rank Reason (see State Rank above)
Agrostis pallens has been found in scattered locations within western Montana. There are fewer than 10 collections in the State Herbaria (University of Montana and Montana State University), and where it is present indications of rarity have not been noted. Most herbaria collections were made in and after 1980. This grass may be under-collected because it can easily be mis-identified as another species of Agrostis. Current data on locations, population sizes, habitat, and threats are needed.
  • Details on Status Ranking and Review
    Leafy Bentgrass (Agrostis pallens) Conservation Status Review
    Review Date = 09/13/2019
    View State Conservation Rank Criteria
    Range Extent

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

    Comment31,466 square kilometers

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    CommentPlant occurs in 7 of the 30,590 4x4 square-kilometer grid cells that cover Montana.

    Number of Populations

    ScoreB - 6 - 20

    Comment7 occurrences

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

    ScoreB - Very few (1-3) occurrences with excellent or good viability or ecological integrity

    Comment3 occurrences described as 'common' or 'moderately abundant' and assumed to be of good viability.

    Environmental Specificity

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

    CommentIn Montana Agrostis pallens grows in moist to wet meadows.

    Threats

    ScoreD - Low

 
General Description
PLANTS: A perennial, rhizomatous (creeping) grass. Stems 60-80 cm tall with most leaves arising from the stems.

LEAVES: Leafy, and generally attached from the lower half of the stem when in flower. Blades are 1.5-11.5 cm long and 2-6 mm wide. When young blades are flat but often become involute (rolled) with age. Ligules 1-6 mm long with the upper margin slightly cut (lacerate), or with irregular notches (erose).

INFLORESCENCE: A contracted to somewhat open panicle with many small flowers, 7–11 cm long. At anthesis (anther dehiscence) the panicle branches spread and ascend. Each node has several primary branches, which branch again along their entire lengths into many small secondary branches.
Spikelets are 3–3.5 mm long, green, yellow-green, or yellow with purple tinges which may make it appear darkish. Glumes are (sub-)equal 2-3.5 mm long, 1(-3) veined, with acute tips. Lemmas are (1.5-)2.2–2.5 mm long, awnless or with an apiculate awn, and with 5 veins which are at least prominent on the upper (distal) portions. Paleas are lacking or minute (to 0.2 mm).

The genus Agrostis comes from the Greek word, agros meaning ‘pasture’ or ‘green fodder’.

Sources: Harvey in FNA 2007; Lesica et al. 2012; and Giblin et al. [eds.] 2018.

Range Comments
Leafy Bentgrass grows from British Columbia south into Baja California, Mexico and east to western Montana and Utah (Harvey in FNA 2007).

Observations in Montana Natural Heritage Program Database
Number of Observations: 8

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

Recency

 

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



Habitat

References
  • Literature Cited AboveLegend:   View Online Publication
    • Flora of North America Editorial Committee. 2007. Flora of North America North of Mexico. Vol. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1. Oxford Univ. Press, New York. xxviii + 911 pp.
    • Giblin, David E., Ben S. Legler, Peter F. Zika, and Richard G. Olmstead (editors). 2018. Flora of the Pacific Northwest: An Illustrated Manual. Second Edition. University of Washington Press in Association with Burke Museum of Natural History and Culture, Seattle, Washington. 882 pp.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Amme, David. No Date. California Agrostis (Bentgrass).
    • Del Moral, Roger, and David M. Wood. 1988. Dynamics of Herbaceous Vegetation Recovery on Mount St. Helens,Washington, USA, after a Volcanic Eruption. Vegetatio, Vol. 74. No. 1, pp. 11-27.
    • 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:
Leafy Bentgrass — Agrostis pallens.  Montana Field Guide.  .  Retrieved on , from