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Montana Field Guides

Narrow-fruited Crisp Moss - Trichostomum tenuirostre
Other Names:  Hairy Mouth Moss, Oxystegus tenuirostris

Status Under Review
Native Species

Global Rank: G5
State Rank: SU

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Acrocarpous. Growing in open to compact, erect clumps ca 0.5-1.5 cm tall (seldom to 3 cm), green or green with brown tones (Crum & Anderson et al. 1981). Stems circular to 5-sided in X-section (FNA 2007).

Leaves: Spreading and somewhat wavy when wet (Lawton 1971), contorted when dry, somewhat cupped, slenderly to widely lance-shaped, 3-6 mm in length, (Crum & Anderson et al. 1981), 0.2-0.6 mm in width (Lawton 1971), plane; margins smooth, faintly dentate (FNA 2007), or somewhat wavy (Crum & Anderson et al. 1981), the upper part flat, unbordered; apex flat or channeled, acute; costa extending slightly beyond the apex to form a mucro (FNA 2007).

Leaf Cells: Costa with ventral cells nearly square (sometimes elongate at the leaf tip); stereid band (sometimes faint) and epidermis present ventrally; dorsally, stereid band faint or lacking and epidermis present. Basal cell area running across the base and forming a "U" or "V" as the cells frequently course upward along the margins slightly, the cells oblong, 3-5:1 (FNA 2007), glossy when dry (Crum & Anderson et al. 1981), fine-walled (Lawton 1971); upper laminal cells nearly square with multiple low papillae per cell, the papillae typically 2-lobed and sometimes fused into 1 large papilla shrouding the cell; the cone-shaped mucro consisting of 3-6 cells (FNA 2007).

Trichostomum tenuirostre var. tenuirostre: Present in Montana.

Trichostomum tenuirostre var. gemmiparum: Unknown in Montana.

Variety tenuirostre: Fruit ripens in the autumn (FNA 2007).

Diagnostic Characteristics
The leaves are quite variable, from delicate and slender to relatively wide (FNA 2007).

Range Comments
Variety tenuirostre
Canada: NT, BC, ON and NB; USA: in the scattered western states of AK, WA, MT, CA, AZ, CO and TX, from MI s to AL, and states east/northeast to the coast (except in the far Southeast); Mexico (FNA 2007). Known in Montana from Flathead County (Elliott 2016).

Variety gemmiparum
USA: MO; Mexico (FNA 2007).

Variety tenuirostre: Calcareous rock and soil (Elliott 2016), cliffs, logs, areas with trickling water (FNA 2007), soil in stony fissures, on visible tree roots in canopied habitats along streams (Smith 1980). Elevation: 0-7550 feet (FNA 2007).

Variety gemmiparum: Vertical cliffs of dolomite (FNA 2007).

Reproductive Characteristics
Dioicous (FNA 2007). Seta 0.7-1.1 cm in length (seldom to 2 cm). Capsule 1.2-1.6 (seldom to 2) mm in length; peristome teeth two-lobed (Crum & Anderson et al. 1981).

Variety tenuirostre: Gemmae lacking (FNA 2007).

Variety gemmiparum: Gemmae brown to russet, several-celled, produced on rhizoids occurring in the soil or on the ventral side of the costa (FNA 2007).

  • Literature Cited AboveLegend:   View Online Publication
    • Crum, H.A. and L.E. Anderson. 1981. Mosses of Eastern North America. 2 volumes. Columbia University Press, New York. 1328 pp.
    • Elliott, J.C. and A.K. Pipp. 2018. A Checklist of Montana Mosses (1880-2018). Updated 3 January, 2020. Montana Natural Heritage Program, Helena, Montana. 73 pp.
    • Flora of North America Editorial Committee, eds. 2007. Flora of North America North of Mexico. Volume 27. Bryophytes: Mosses, Part 1. Oxford University Press, Inc., NY. xxi + 713 pp.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
    • Smith, A.J.E. 1980. The Moss Flora of Britain and Ireland. Cambridge University Press, Cambridge. 705 pp.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Flowers, S. 1973. Mosses: Utah and the West. Brigham Young University, Provo, Utah. 567 p.
    • Lawton, E. 1971. Keys for the Identification of the Mosses on the Pacific Northwest. Reprinted from 'Moss Flora of the Pacific Northwest'. Published as Supplement No. 2 of the Journal of the Hattori Botanical Laboratory. Nichinan, Miyazaki, Japan. 66 pp.
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Narrow-fruited Crisp Moss — Trichostomum tenuirostre.  Montana Field Guide.  .  Retrieved on , from