Search Field Guide
Advanced Search
MT Gov Logo
Montana Field Guide

Montana Field Guides

Warnstorfia Moss - Sarmentypnum exannulatum
Other Names:  Warnstorfia exannulata

Species of Concern
Native Species

Global Rank: G5
State Rank: S1

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Green, tending toward yellow, or with pure red coloring. Stems with radial branching; possessing a central strand (FNA 2007).

Leaves: Stem leaves egg-shaped to somewhat deltoid, cupped, tapering slowly to the sickle-shaped (occasionally straight) apex; apex gradually tapered, ending in a narrow point, sometimes moderately longitudinally creased; base not extending down the stem; lower or upper margins (sometimes both upper and lower) with noticeable fine teeth; costa reaching 3/5 to most of the leaf length (FNA 2007).

Leaf Cells: Axillary hairs with up to 4 distal cells, hyaline when immature; alar area well-differentiated, extending from margins to or almost to the nerve, the cells swollen, fine-walled, hyaline (or red to brownish when mature); marginal cells frequently distinguished from the medial cells, becoming quite rectangular or widened or both (this characteristic quite variable, however) (FNA 2007).

Diagnostic Characteristics
Of wetland species that have gradually tapering and curving leaves toward the apex, W. exannulatum is one of the most common (FNA 2007).

The alar areas of the similar Warnstorfia fluitans generally do not extend as far distally as those of W. exannulatum. However, W. exannulatum does have phenotypes in which the alar region varies in its distal extension (FNA 2007).

Species Range

Range Comments
In North America: Present in most Canadian provinces and territories; in the USA, found from MT to CO, w to the coastal states, also in scattered states of the northeast (FNA 2007). Known in Montana from Carbon, Beaverhead, Flathead, Glacier, Lake, Missoula, and Stillwater Counties (Elliott 2016).

Observations in Montana Natural Heritage Program Database
Number of Observations: 18

(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)

Soil and humus in lakes (Elliott 2016), near springs, late-melting snow patches, fens somewhat rich in minerals, underwater in lakes. Elevation: 0-13,780 feet (FNA 2007).

Reproductive Characteristics
Dioicous (FNA 2007).

  • 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.
  • 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.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
  • Web Search Engines for Articles on "Warnstorfia Moss"
Login Logout
Citation for data on this website:
Warnstorfia Moss — Sarmentypnum exannulatum.  Montana Field Guide.  .  Retrieved on , from