Cyrto-hypnum pygmaeum    (Schimp. in B.S.G.) Buck & Crum

Pygmy Plume Moss 

MN Status:
special concern
Federal Status:


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Minnesota range map
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North American range map
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Thuidium pygmaeum

  Basis for Listing

Cyrto-hypnum pygmaeum (pygmy plume moss) is an endemic in eastern North America, within the temperate bioclimatic zone. It has been recorded regionally from Ontario, Iowa, Wisconsin, and the Upper Peninsula of Michigan. In Minnesota, only four populations have been found in The Blufflands of Goodhue, Wabasha, Winona, and Houston counties. Cyrto-hypnum pygmaeum is a non-aggressive perennial that forms smooth mats in mesic forests, on cliffs, and in rocky creek bed habitat. Because only a few populations have been documented in Minnesota, there is too little information available to detect a statewide population trend at this time. Further inventory work is needed to clarify the species’ abundance and distribution in the state as well as the potential threats to its survival (Janssens 2005). Due to its apparent rarity and restricted habitat requirements, Cyrto-hypnum pygmaeum was designated a species of special concern in 2013.


Cyrto-hypnum pygmaeum is a dark-green plant and, as its name suggests, it is indeed small (Crum and Anderson 1981). It is best recognized by its creeping bi-pinnately branched stems that are distinctly papillose (having minute round bumps or projections). Stems are 1.0-2.0 cm (0.4-0.8 in.) long, with abundant paraphyllia on both primary stems and branches. Branch leaves are erect to in-curved when dry, narrowly acuminate from a broadly triangular base, and 0.2-0.3 mm (0.008- 0.012 in.) long on primary branches, 0.2 mm (0.008 in.) on secondary branches. Leaf apex is acute; costa (midrib) is ½-3/4 the length of the leaf, with margins papillose-crenulate. Setae (stalk supporting the capsule) are 7.0-17.0 mm (0.3-0.7 in.) long, smooth, and red. Capsules are 0.7-1.2 mm (0.03-0.05 in.) long, oblong to cylindric, asymmetric, and inclined to horizontal.


Cyrto-hypnum pygmaeum prefers moist woods on shaded limestone or sandstone and, less often, quartzite. It is often found on rocks in stream valleys (rarely on logs) in woodlands and forests, such as southern dry-mesic oak forest, southern mesic oak-basswood forest, southern mesic maple-basswood forest, or southern wet-mesic hardwood forest.

  Biology / Life History

This species is autoicous (male and female reproductive organs in separate inflorescences on the same plant).

  Conservation / Management

Given its specific local microhabitat preferences in the Driftless Area (Paleozoic Plateau), climate change may eventually stress survival of the existing populations in the state.

  Best Time to Search

Capsules mature July—Sept; however, the best time to search for Cyrto-hypnum pygmaeum is anytime from May through September or essentially anytime the ground is not covered by snow.


Erika Rowe (MNDNR), 2018

(Note: all content ©MNDNR)

  References and Additional Information

Buck, W. R. 2007. Thuidiaceae in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 28. <>. Accessed 03 October 2016.

Crum, H. A., and L. E. Anderson. 1981. Mosses of eastern North America. In two volumes. Columbia University Press, New York, Yew York. 1330 pp.

Janssens, J. A. 2000. Bryophytes of the Paleozoic Plateau Ecological Region, southeastern Minnesota. I. Non-transect data submitted to the Minnesota Department of Natural Resources, County Biological Survey, St. Paul.

Janssens, J. A. 2005. Proposed candidates of endangered, threatened, and special concern species of bryophytes for Minnesota: update June 2005. Report to the Minnesota Department of Natural Resources, County Biological Survey, St. Paul. 18 pp.

Janssens, J. A. 2009. MS Access database on Minnesota bryophytes. Lambda-Max Ecological Research, Minneapolis, Minnesota.

Minnesota Department of Natural Resources. 2005. Field guide to the native plant communities of Minnesota: the eastern broadleaf forest province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 394 pp.

NatureServe. 2009. NatureServe Explorer: an online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. <http.//>. Accessed 10 June 2009.

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