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Montana Field Guides

A Fern Moss - Hypnum callichroum
Other Names:  A Hypnum Moss

Status Under Review
Native Species

Global Rank: G5?
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Pleurocarpous, growing in mats, shiny (Lawton 1971), light green to green with yellow tones. Stems prostrate to upwardly inclined, pinnate, sometimes irregularly so, 2-6 cm, yellow-green to greenish-yellow; branches 2-10 mm in length; hyalodermis and central strand both in attendance; pseudoparaphyllia lance-shaped (FNA 2014); cortical stem cells hyaline, big (Lawton 1971).

Stem Leaves: Curved in sickle-like fashion or rolled into a circle at the leaf apex and turned in one direction, 1.5-2 mm in length, to 0.8 mm in width (FNA 2014), cupped (Lawton 1971), egg-shaped to somewhat lance-shaped, slowly tapering to the thin (FNA 2014), thread-like acumen (Lawton 1971), the base extending down the stem; leaf edges flat, saw-toothed near the tip; costa paired, short; branch leaves akin to stem leaves (FNA 2014).

Leaf Cells: Laminal cells not papillose; medial laminal cells longer and narrower than the basal cells (FNA 2014), with thick, non-porose walls (Lawton 1971); basal laminal cells colored yellow ranging to green, the walls porose; alar cells suddenly inflated, fine-walled, extending 1-3 cells up and along the margin, with several square to deltoid cells bounding the swollen cells distally, the alar cells distinct from adjacent cells (FNA 2014).

Fruit ripens in summer (FNA 2014).

Diagnostic Characteristics
The hyalodermis presence and conspicuous alar regions with fine-walled cells are dependable characters, although identification without fruit may be difficult (FNA 2014).

Range Comments
North American Range

AK, BC and AB, WA (FNA 2014). Known in Montana from Lake, Lewis and Clark, and Lincoln Counties (Elliott and Pipp 2016).

Observations in Montana Natural Heritage Program Database
Number of Observations: 3

(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)

Growing on trees or on the ground (FNA 2014), tree bases, soil, and stone (Elliott and Pipp 2016), occasionally among grasses (Lawton 1971), in woods or more open areas. Occurring from lowlands to about 4920 feet elevation (FNA 2014).

Reproductive Characteristics
Dioicous, with sporophytes often produced by epiphytic plants, seldom by those on the ground (FNA 2014). Perigonia borne on stems, the bracts short (Lawton 1971). Exterior perichaetial bracts bent back and downward; interior perichaetial bracts upright (FNA 2014), sometimes reaching 4 mm in length (Lawton 1971), with a thin acumen and the apical margins dentate. Seta 20-35 mm tall, russet, smooth. Capsule 1.5-2 mm in length, russet, tilted (FNA 2014), bowed, shrunken below the opening when dry (Lawton 1971); operculum cone-shaped; exostome teeth 16, with a zigzag line on the outer face, fine lines or ridges below, and papillae above; endostome processes 16, similar in height to the teeth, keeled, cilia with short, crosswise projections. Calyptra hairless and draping hood-like (FNA 2014).

  • Literature Cited AboveLegend:   View Online Publication
    • 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. 2014. Flora of North America North of Mexico. Volume 28. Bryophytes: Mosses, Part 2. Oxford University Press, Inc., NY. xxi + 702 pp.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • 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.
    • Smith, A.J.E. 1980. The Moss Flora of Britain and Ireland. Cambridge University Press, Cambridge. 705 pp.
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Citation for data on this website:
A Fern Moss — Hypnum callichroum.  Montana Field Guide.  .  Retrieved on , from